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Abstract
The disease burden of typhoid fever remains high in endemic areas in Asia and Africa, especially in children. Recent clinical trials conducted by the Typhoid Vaccine Acceleration Consortium show typhoid conjugate vaccine (TCV) to be safe, immunogenic, and efficacious at preventing blood culture-confirmed typhoid fever in African and Asian children. Pakistan, Liberia, and Zimbabwe recently introduced TCV through campaigns and routine childhood immunizations, providing protection for this vulnerable population. It is essential to continue this momentum while simultaneously filling data gaps - including typhoid complications - to inform decision-making on TCV introduction. A multidisciplinary approach including surveillance, water, sanitation, and hygiene investments, and large-scale TCV introduction is needed to decrease the burden and mortality of typhoid fever.
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Affiliation(s)
- Megan Birkhold
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Aziza Mwisongo
- Center for Vaccine Innovation and Access, PATH
, Seattle, Washington, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Correspondence: Kathleen M. Neuzil, MD, MPH, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, 685 W Baltimore Street, Room 480, Baltimore, MD 21201 ()
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Qadri F, Khanam F, Liu X, Theiss-Nyland K, Biswas PK, Bhuiyan AI, Ahmmed F, Colin-Jones R, Smith N, Tonks S, Voysey M, Mujadidi YF, Mazur O, Rajib NH, Hossen MI, Ahmed SU, Khan A, Rahman N, Babu G, Greenland M, Kelly S, Ireen M, Islam K, O'Reilly P, Scherrer KS, Pitzer VE, Neuzil KM, Zaman K, Pollard AJ, Clemens JD. Protection by vaccination of children against typhoid fever with a Vi-tetanus toxoid conjugate vaccine in urban Bangladesh: a cluster-randomised trial. Lancet 2021; 398:675-684. [PMID: 34384540 PMCID: PMC8387974 DOI: 10.1016/s0140-6736(21)01124-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Typhoid fever remains a major cause of morbidity and mortality in low-income and middle-income countries. Vi-tetanus toxoid conjugate vaccine (Vi-TT) is recommended by WHO for implementation in high-burden countries, but there is little evidence about its ability to protect against clinical typhoid in such settings. METHODS We did a participant-masked and observer-masked cluster-randomised trial preceded by a safety pilot phase in an urban endemic setting in Dhaka, Bangladesh. 150 clusters, each with approximately 1350 residents, were randomly assigned (1:1) to either Vi-TT or SA 14-14-2 Japanese encephalitis (JE) vaccine. Children aged 9 months to less than 16 years were invited via parent or guardian to receive a single, parenteral dose of vaccine according to their cluster of residence. The study population was followed for an average of 17·1 months. Total and overall protection by Vi-TT against blood culture-confirmed typhoid were the primary endpoints assessed in the intention-to-treat population of vaccinees or all residents in the clusters. A subset of approximately 4800 participants was assessed with active surveillance for adverse events. The trial is registered at www.isrctn.com, ISRCTN11643110. FINDINGS 41 344 children were vaccinated in April-May, 2018, with another 20 412 children vaccinated at catch-up vaccination campaigns between September and December, 2018, and April and May, 2019. The incidence of typhoid fever (cases per 100 000 person-years) was 635 in JE vaccinees and 96 in Vi-TT vaccinees (total Vi-TT protection 85%; 97·5% CI 76 to 91, p<0·0001). Total vaccine protection was consistent in different age groups, including children vaccinated at ages under 2 years (81%; 95% CI 39 to 94, p=0·0052). The incidence was 213 among all residents in the JE clusters and 93 in the Vi-TT clusters (overall Vi-TT protection 57%; 97·5% CI 43 to 68, p<0·0001). We did not observe significant indirect vaccine protection by Vi-TT (19%; 95% CI -12 to 41, p=0·20). The vaccines were well tolerated, and no serious adverse events judged to be vaccine-related were observed. INTERPRETATION Vi-TT provided protection against typhoid fever to children vaccinated between 9 months and less than 16 years. Longer-term follow-up will be needed to assess the duration of protection and the need for booster doses. FUNDING The study was funded by the Bill & Melinda Gates Foundation.
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Affiliation(s)
- Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh.
| | - Farhana Khanam
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Xinxue Liu
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Katherine Theiss-Nyland
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | | | - Amirul Islam Bhuiyan
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Faisal Ahmmed
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Rachel Colin-Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Nicola Smith
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Susan Tonks
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Yama F Mujadidi
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Olga Mazur
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Nazmul Hasan Rajib
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Md Ismail Hossen
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Shams Uddin Ahmed
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Arifuzzaman Khan
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Nazia Rahman
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Golap Babu
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Melanie Greenland
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Sarah Kelly
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Mahzabeen Ireen
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Kamrul Islam
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Peter O'Reilly
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Karin Sofia Scherrer
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT USA
| | | | - K Zaman
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - John D Clemens
- International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh; University of California Los Angeles, Fielding School of Public Health, Los Angeles, CA, USA
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Affiliation(s)
- Buddha Basnyat
- Oxford University Clinical Research Unit-Patan Academy of Health Science Kathmandu, Nepal
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
| | | | | | | | - Christopher M Parry
- Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, UK
- Alder Hey Children' Hospital and Liverpool University Hospitals. Liverpool, UK
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Dhara D, Baliban SM, Huo CX, Rashidijahanabad Z, Sears KT, Nick ST, Misra AK, Tennant SM, Huang X. Syntheses of Salmonella Paratyphi A Associated Oligosaccharide Antigens and Development towards Anti-Paratyphoid Fever Vaccines. Chemistry 2020; 26:15953-15968. [PMID: 32578281 PMCID: PMC7722144 DOI: 10.1002/chem.202002401] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/21/2020] [Indexed: 01/08/2023]
Abstract
With the emergence of multidrug resistant Salmonella strains, the development of anti-Salmonella vaccines is an important task. Currently there are no approved vaccines against Salmonella Paratyphi A, the leading cause of paratyphoid fever. To fill this gap, oligosaccharides corresponding to the O-polysaccharide repeating units from the surface of Salmonella Paratyphi A have been synthesized through convergent stereoselective glycosylations. The synthetic glycan antigen was conjugated with a powerful immunogenic carrier system, the bacteriophage Qβ. The resulting construct was able to elicit strong and long-lasting anti-glycan IgG antibody responses, which were highly selective toward Salmonella Paratyphi A associated glycans. The availability of well-defined glycan antigen enabled the determination that one repeating unit of the polysaccharide is sufficient to induce protective antibodies, and the paratose residue and/or the O-acetyl modifications on the backbone are important for recognition by antibodies elicited by a Qβ-tetrasaccharide conjugate. Immune sera provided excellent protection to mice from lethal challenge with Salmonella Paratyphi A, highlighting the potential of the synthetic glycan-based vaccine.
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Affiliation(s)
- Debashis Dhara
- Division of Molecular Medicine; Bose Institute, P-1/12, C.I.T. Scheme VII M; Kolkata 700054, India
| | - Scott M. Baliban
- Center for Vaccine Development and Global Health; University of Maryland School of Medicine; Baltimore, MD, USA
| | - Chang-Xin Huo
- Department of Chemistry, Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
- Institute for Quantitative Health Science & Engineering; Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
| | - Zahra Rashidijahanabad
- Department of Chemistry, Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
- Institute for Quantitative Health Science & Engineering; Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
| | - Khandra T. Sears
- Center for Vaccine Development and Global Health; University of Maryland School of Medicine; Baltimore, MD, USA
| | - Setare Tahmasebi Nick
- Department of Chemistry, Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
- Institute for Quantitative Health Science & Engineering; Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
| | - Anup Kumar Misra
- Division of Molecular Medicine; Bose Institute, P-1/12, C.I.T. Scheme VII M; Kolkata 700054, India
| | - Sharon M. Tennant
- Center for Vaccine Development and Global Health; University of Maryland School of Medicine; Baltimore, MD, USA
| | - Xuefei Huang
- Department of Chemistry, Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
- Institute for Quantitative Health Science & Engineering; Michigan State University; 578 South Shaw Lane, East Lansing, MI 48824, USA
- Department of Biomedical Engineering; Michigan State University; East Lansing, MI 48824, USA
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Kilpatrick KW, Hudgens MG, Halloran ME. Estimands and inference in cluster-randomized vaccine trials. Pharm Stat 2020; 19:710-719. [PMID: 32372535 PMCID: PMC8273646 DOI: 10.1002/pst.2026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/18/2020] [Accepted: 04/02/2020] [Indexed: 11/08/2022]
Abstract
Cluster-randomized trials are often conducted to assess vaccine effects. Defining estimands of interest before conducting a trial is integral to the alignment between a study's objectives and the data to be collected and analyzed. This paper considers estimands and estimators for overall, indirect, and total vaccine effects in trials, where clusters of individuals are randomized to vaccine or control. The scenario is considered where individuals self-select whether to participate in the trial, and the outcome of interest is measured on all individuals in each cluster. Unlike the overall, indirect, and total effects, the direct effect of vaccination is shown in general not to be estimable without further assumptions, such as no unmeasured confounding. An illustrative example motivated by a cluster-randomized typhoid vaccine trial is provided.
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Affiliation(s)
- Kayla W. Kilpatrick
- Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
| | - Michael G. Hudgens
- Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
| | - M. Elizabeth Halloran
- Center for Inference and Dynamics of Infectious Diseases, Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, Washington
- Department of Biostatistics, University of Washington, Seattle, Washington
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Abstract
Background Empiric prescribing of antimicrobials in typhoid-endemic settings has increased selective pressure on the development of antimicrobial-resistant Salmonella enterica serovar Typhi. The introduction of typhoid conjugate vaccines (TCVs) in these settings may relieve this selective pressure, thereby reducing resistant infections and improving health outcomes. Methods A deterministic transmission dynamic model was developed to simulate the impact of TCVs on the number and proportion of antimicrobial-resistant typhoid infections and chronic carriers. One-way sensitivity analyses were performed to ascertain particularly impactful model parameters influencing the proportion of antimicrobial-resistant infections and the proportion of cases averted over 10 years. Results The model simulations suggested that increasing vaccination coverage would decrease the total number of antimicrobial-resistant typhoid infections but not affect the proportion of cases that were antimicrobial resistant. In the base-case scenario with 80% vaccination coverage, 35% of all typhoid infections were antimicrobial resistant, and 44% of the total cases were averted over 10 years by vaccination. Vaccination also decreased both the total number and proportion of chronic carriers of antimicrobial-resistant infections. The prevalence of chronic carriers, recovery rates from infection, and relative fitness of resistant strains were identified as crucially important parameters. Conclusions Model predictions for the proportion of antimicrobial resistant infections and number of cases averted depended strongly on the relative fitness of the resistant strain(s), prevalence of chronic carriers, and rates of recovery without treatment. Further elucidation of these parameter values in real-world typhoid-endemic settings will improve model predictions and assist in targeting future vaccination campaigns and treatment strategies.
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Affiliation(s)
- Samantha Kaufhold
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut
- Present address: Analysis Group, 31 Menlo Park, CA 94025
| | - Reza Yaesoubi
- Department of Health Policy and Management, Yale School of Public Health, Yale University, New Haven, Connecticut
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut
- Correspondence: V. E. Pitzer, Yale School of Public Health, P.O. Box 208034, New Haven, CT 06520-8034 ()
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Thakur R, Pathania P, Kaur N, Joshi V, Kondepudi KK, Suri CR, Rishi P. Prophylactic potential of cytolethal distending toxin B (CdtB) subunit of typhoid toxin against Typhoid fever. Sci Rep 2019; 9:18404. [PMID: 31804525 PMCID: PMC6895121 DOI: 10.1038/s41598-019-54690-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 11/18/2019] [Indexed: 02/04/2023] Open
Abstract
Typhoid fever caused by Salmonella enterica serovar Typhi (S.Typhi) continues to be a major problem, especially in developing countries. Due to the rapid emergence of multi-drug-resistant (MDR) strains, which limits the efficacy of conventional antibiotics as well as problems associated with the existing vaccines, efforts are being made to develop effective prophylactic agents. CdtB subunit of typhoid toxin was selected for assessing its vaccine potential due to its high conservation throughout the Typhi strains. In-vitro assessment of DNase activity of cloned and purified CdtB protein showed a significant decrease in the band intensity of DNA. The measure of metabolic activity and morphological alterations assessed using different cell lines in the presence of CdtB protein showed no significant signs of toxicity. These observations were further strengthened by cell cycle analysis, assessed by flow cytometry. Keeping these observations in mind, the immunoprotective potential of CdtB was assessed using S.Typhi induced mouse peritonitis model. A significant titer of IgG antibodies (>128000) against CdtB protein was recorded in the immunized mice by enzyme-linked immunosorbent assay (ELISA), which was also validated by immunoblotting. Active immunization with the protein protected 75% mice against a lethal dose of S.Typhi Ty2. The data indicated a significant (up to 5 log) reduction in the bacterial load in the spleen and liver of immunized-infected mice compared to control (unimmunized-infected) mice which might have resulted in the modulation of histoarchitecture of spleen and liver and the levels of cytokines (IL-6, TNF-α and IL-10) production; thereby indicating the effectiveness of the subunit. The observations deduced from the study give the proof of concept of immunogenic potential of protein. However, further studies involving the immunoreactivity of CdtB with the statistically significant number of sera samples obtained from the human patients would be helpful in establishing the relevance of CdtB protein in humans and for making the strategies to develop it as an effective vaccine candidate.
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Affiliation(s)
- Reena Thakur
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Preeti Pathania
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Navneet Kaur
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Vattan Joshi
- Department of Microbiology, Panjab University, Chandigarh, India
| | | | | | - Praveen Rishi
- Department of Microbiology, Panjab University, Chandigarh, India.
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Abstract
The Typhoid Surveillance in Africa Program (TSAP) and the Severe Typhoid Fever in Africa (SETA) program have refined our understanding of age and geographic distribution of typhoid fever and other invasive salmonelloses in Africa and will help inform future typhoid control strategies, namely, introduction of typhoid conjugate vaccines.
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Affiliation(s)
- Megan E Carey
- Enteric and Diarrheal Diseases, Global Health, Bill & Melinda Gates Foundation, Seattle, Washington
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - A Duncan Steele
- Enteric and Diarrheal Diseases, Global Health, Bill & Melinda Gates Foundation, Seattle, Washington
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Pitzer VE, Meiring J, Martineau FP, Watson CH, Kang G, Basnyat B, Baker S. The Invisible Burden: Diagnosing and Combatting Typhoid Fever in Asia and Africa. Clin Infect Dis 2019; 69:S395-S401. [PMID: 31612938 PMCID: PMC6792124 DOI: 10.1093/cid/ciz611] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Measuring the burden of typhoid fever and developing effective strategies to reduce it require a surveillance infrastructure that is currently lacking in many endemic countries. Recent efforts and partnerships between local and international researchers have helped to provide new data on the incidence and control of typhoid in parts of Asia and Africa. Here, we highlight examples from India, Nepal, Vietnam, Fiji, Sierra Leone, and Malawi that summarize past and present experiences with the diagnosis, treatment, and prevention of typhoid fever in different locations with endemic disease. While there is no validated road map for the elimination of typhoid, the lessons learned in studying the epidemiology and control of typhoid in these settings can provide insights to guide future disease control efforts.
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Affiliation(s)
- Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut
| | - James Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
| | | | - Conall H Watson
- Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, United Kingdom
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
| | - Gagandeep Kang
- Translational Health Sciences Technology Institute, Faridabad, Haryana, India
| | - Buddha Basnyat
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, United Kingdom
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Stephen Baker
- Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Department of Medicine, University of Cambridge, United Kingdom
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10
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Abstract
BACKGROUND In the decades following the discovery of the bacillus causing typhoid, in 1880, understanding of the disease formerly known as enteric fever was transformed, offering new possibilities for prevention. Gradually, measures that aimed to prevent infection from human carriers were developed, as were inoculations designed to confer immunity against typhoid and paratyphoid fevers. These were initially introduced in European armies that were regularly ravaged by typhoid, especially garrisons stationed in the colonies. This article reviews the research undertaken in the armed forces and the measures that they implemented in the years up to and during the First World War. METHODS The article is based on an analytical review of scientific literature from the early 19th century, focusing on the United Kingdom, Germany, and France. RESULTS The armies of the United Kingdom, Germany, and France undertook important work on the transmission of typhoid in the years between 1890 and 1918. Many preventive measures were introduced to deal with the spread of typhoid but these varied between the 3 countries, depending largely on their political traditions. Inoculation was particularly successful in preventing typhoid and greatly reduced the number of casualties from this disease during the First World War. Despite this, it proved difficult to prevent paratyphoid infection, and debates continued over which vaccines to use and whether or not immunization should be voluntary. CONCLUSIONS By the end of the First World War, the value of inoculation in preventing the spread of typhoid had been proven. Its successful implementation demonstrates the importance of vaccination as a public health intervention during times of conflict and social upheaval.
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Affiliation(s)
- Christoph Gradmann
- Department of Community Medicine and Global Health, University of Oslo, Norway
| | | | - Anne Rasmussen
- Centre Alexandre-Koyré, Ecole des hautes études en sciences sociales, Centre national de la recherche scientifique, Muséum national d’Histoire naturelle de Paris, France
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Meiring JE, Giubilini A, Savulescu J, Pitzer VE, Pollard AJ. Generating the Evidence for Typhoid Vaccine Introduction: Considerations for Global Disease Burden Estimates and Vaccine Testing Through Human Challenge. Clin Infect Dis 2019; 69:S402-S407. [PMID: 31612941 PMCID: PMC6792111 DOI: 10.1093/cid/ciz630] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Typhoid fever has had a major impact on human populations, with the causative pathogen Salmonella enterica serovar Typhi implicated in many outbreaks through history. The current burden of disease is estimated at 11-18 million infections annually, with the majority of infections located in Africa and South Asia. Data that have been used to estimate burden are limited to a small number of blood-culture surveillance studies, largely from densely populated urban centers. Extrapolating these data to estimate disease burden within and across countries highlights the lack of precision in global figures. A number of approaches have been developed, characterizing different geographical areas by water-based risk factors for typhoid infection or broader measures of health and development to more accurately extrapolate incidence. Recognition of the substantial disease burden is essential for policy-makers considering vaccine introduction. Typhoid vaccines have been in development for >100 years. The Vi polysaccharide (ViPS) and Ty21a vaccines have had a World Health Organization (WHO) recommendation for programmatic use in countries with high burden for 10 years, with 1 ViPS vaccine also having WHO prequalification. Despite this, uptake and introduction of these vaccines has been minimal. The development of a controlled human infection model (CHIM) enabled the accelerated testing of the newly WHO-prequalified ViPS-tetanus toxoid protein conjugate vaccine, providing efficacy estimates for the vaccine, prior to larger field trials. There is an urgency to the global control of enteric fever due to the escalating problem of antimicrobial resistance. With more accurate burden of disease estimates and a vaccine showing efficacy in CHIM, that control is now a possibility.
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Affiliation(s)
- James E Meiring
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, United Kingdom
| | - Alberto Giubilini
- Oxford Uehiro Centre for Practical Ethics, University of Oxford, United Kingdom
| | - Julian Savulescu
- Oxford Uehiro Centre for Practical Ethics, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, Connecticut
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
- National Institute for Health Research Oxford Biomedical Research Centre, University of Oxford, United Kingdom
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Yin J, Cheng Z, Wu Y, He Q, Zhang J, Yang Z, Ding S, Li J, Guo D. Characterization and protective efficacy of a Salmonella pathogenicity island 2 (SPI2) mutant of Salmonella Paratyphi A. Microb Pathog 2019; 137:103795. [PMID: 31610219 DOI: 10.1016/j.micpath.2019.103795] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/15/2019] [Accepted: 10/10/2019] [Indexed: 11/18/2022]
Abstract
Paratyphoid fever caused by Salmonella Paratyphi A is a serious public health problem in many countries. In order to and develop a live attenuated candidate vaccine of Salmonella Paratyphi A, a Salmonella pathogenicity island 2 (SPI2, approximate 40 kb) deletion mutant of Salmonella Paratyphi A was constructed by lambda Red recombination, then the biological characteristics and protective ability of the Salmonella Paratyphi A SPI2 mutant were evaluated. Our results showed that the growth and biochemical properties of the SPI2 mutant were consistent with that of its parent strain, and the mutant was stable with the loss of SPI2. The mice lethal test showed that the virulence of the SPI2 mutant was significantly decreased, it can colonize and persistent more than 14 days in the liver and spleen of mice. Vaccination with the SPI2 mutant in mice revealed no significant effect on body weight and clinical symptoms compared to control animals, and specific humoral and cellular immune responses were also significantly induced. Immunization of mice offered efficient protection against Salmonella Paratyphi A strain challenge at 14 days post vaccination based on mortality and clinical symptoms relative to control group. Overall, these findings suggested that SPI2 plays an important role in pathogenicity of Salmonella Paratyphi A, and the SPI2 mutant showed its potential to develop a live attenuated vaccine candidate.
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Affiliation(s)
- Junlei Yin
- School of Life Science and Technology, Xinxiang University, Xinxiang, China.
| | - Zhao Cheng
- School of Life Science and Technology, Xinxiang University, Xinxiang, China
| | - Yuchen Wu
- School of Life Science and Technology, Xinxiang University, Xinxiang, China
| | - Qunli He
- Medical College, Zhengzhou University of Industrial Technology, Zhengzhou, China; College of Basic Medicine, Xinxiang Medical University, Xinxiang, China
| | - Jingjing Zhang
- Medical College, Zhengzhou University of Industrial Technology, Zhengzhou, China
| | - Zhanfeng Yang
- Medical College, Zhengzhou University of Industrial Technology, Zhengzhou, China
| | - Shuming Ding
- Medical College, Zhengzhou University of Industrial Technology, Zhengzhou, China
| | - Jizong Li
- Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Dongguang Guo
- School of Life Science and Technology, Xinxiang University, Xinxiang, China
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Basnyat B, Karkey A. Tackling typhoid fever in South Asia: lessons from Vietnam. Lancet Glob Health 2019; 7:e1317-e1318. [PMID: 31537355 DOI: 10.1016/s2214-109x(19)30320-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 07/07/2019] [Indexed: 11/19/2022]
Affiliation(s)
- Buddha Basnyat
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Science, Kathmandu, PO Box 3596, Nepal.
| | - Abhilasha Karkey
- Oxford University Clinical Research Unit-Nepal, Patan Academy of Health Science, Kathmandu, PO Box 3596, Nepal
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14
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Bilcke J, Antillón M, Pieters Z, Kuylen E, Abboud L, Neuzil KM, Pollard AJ, Paltiel AD, Pitzer VE. Cost-effectiveness of routine and campaign use of typhoid Vi-conjugate vaccine in Gavi-eligible countries: a modelling study. Lancet Infect Dis 2019; 19:728-739. [PMID: 31130329 PMCID: PMC6595249 DOI: 10.1016/s1473-3099(18)30804-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/10/2018] [Accepted: 12/14/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND Typhoid fever is a major cause of morbidity and mortality in low-income and middle-income countries. In 2017, WHO recommended the programmatic use of typhoid Vi-conjugate vaccine (TCV) in endemic settings, and Gavi, The Vaccine Alliance, has pledged support for vaccine introduction in these countries. Country-level health economic evaluations are now needed to inform decision-making. METHODS In this modelling study, we compared four strategies: no vaccination, routine immunisation at 9 months, and routine immunisation at 9 months with catch-up campaigns to either age 5 years or 15 years. For each of the 54 countries eligible for Gavi support, output from an age-structured transmission-dynamic model was combined with country-specific treatment and vaccine-related costs, treatment outcomes, and disability weights to estimate the reduction in typhoid burden, identify the strategy that maximised average net benefit (ie, the optimal strategy) across a range of country-specific willingness-to-pay (WTP) values, estimate and investigate the uncertainties surrounding our findings, and identify the epidemiological conditions under which vaccination is optimal. FINDINGS The optimal strategy was either no vaccination or TCV immunisation including a catch-up campaign. Routine vaccination with a catch-up campaign to 15 years of age was optimal in 38 countries, assuming a WTP value of at least US$200 per disability-adjusted life-year (DALY) averted, or assuming a WTP value of at least 25% of each country's gross domestic product (GDP) per capita per DALY averted, at a vaccine price of $1·50 per dose (but excluding Gavi's contribution according to each country's transition phase). This vaccination strategy was also optimal in 48 countries assuming a WTP of at least $500 per DALY averted, in 51 with assumed WTP values of at least $1000, in 47 countries assuming a WTP value of at least 50% of GDP per capita per DALY averted, and in 49 assuming a minimum of 100%. Vaccination was likely to be cost-effective in countries with 300 or more typhoid cases per 100 000 person-years. Uncertainty about the probability of hospital admission (and typhoid incidence and mortality) had the greatest influence on the optimal strategy. INTERPRETATION Countries should establish their own WTP threshold and consider routine TCV introduction, including a catch-up campaign when vaccination is optimal on the basis of this threshold. Obtaining improved estimates of the probability of hospital admission would be valuable whenever the optimal strategy is uncertain. FUNDING Bill & Melinda Gates Foundation, Research Foundation-Flanders, and the Belgian-American Education Foundation.
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Affiliation(s)
- Joke Bilcke
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.
| | - Marina Antillón
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Zoë Pieters
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium; Center for Statistics, I-Biostat, Hasselt University, Diepenbeek, Belgium
| | - Elise Kuylen
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Linda Abboud
- Centre for Health Economics Research and Modeling Infectious Diseases, Vaccine and Infectious Disease Institute, University of Antwerp, Antwerp, Belgium
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK
| | - A David Paltiel
- Department of Health Policy and Management, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT, USA.
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15
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Srinivasan M, Sindhu KN, John J, Kang G. Opportunities for Typhoid Vaccination in India. Indian Pediatr 2019; 56:453-458. [PMID: 31278221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Typhoid fever, an infection with potentially life threatening complications, is responsible for 11 to 21 million illness episodes and 145,000 to 161,000 deaths each year globally. India is a high burden country and also faces the challenge of antimicrobial resistance, which further narrows treatment options. This review analyzes the need for typhoid vaccination in India, and appraises the evidence on efficacy, immunogenicity and cost-effectiveness of currently available typhoid vaccines. In 2018, WHO prequalified the first typhoid conjugate vaccine Vi-TT and recommended it for children aged 6-23 months, along with measles vaccine at 9 or 15 months of age through the expanded programme on immunization. With the high endemicity of typhoid in India and the proven cost-effectiveness of the conjugate vaccine, a roll-out of typhoid vaccine should be considered at the earliest.
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Affiliation(s)
| | | | - Jacob John
- Department of Community Health, Christian Medical College, Vellore, India
| | - Gagandeep Kang
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, India. Correspondence to: Dr Gagandeep Kang, The Wellcome Trust Research Laboratory, Division of Gastrointestinal Sciences, Christian Medical College, Vellore 632 002, Tamil Nadu, India.
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16
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Affiliation(s)
- Andrew J Pollard
- Oxford Vaccine Group, University of Oxford, and the National Institute for Health Research Oxford Biomedical Research Centre, United Kingdom
| | - Anthony A Marfin
- Center for Vaccine Innovation and Access, PATH, Seattle, Washington
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health at the University of Maryland School of Medicine, Baltimore, MD
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17
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Abstract
BACKGROUND Contemporary incidence estimates of typhoid fever are needed to guide policy decisions and control measures and to improve future epidemiological studies. METHODS We systematically reviewed 3 databases (Ovid Medline, PubMed, and Scopus) without restriction on age, country, language, or time for studies reporting the incidence of blood culture-confirmed typhoid fever. Outbreak, travel-associated, and passive government surveillance reports were excluded. We performed a meta-analysis using a random-effects model to calculate estimates of pooled incidence, stratifying by studies that reported the incidence of typhoid fever and those that estimated incidence by using multipliers. RESULTS Thirty-three studies were included in the analysis. There were 26 study sites from 16 countries reporting typhoid cases from population-based incidence studies, and 17 sites in 9 countries used multipliers to account for underascertainment in sentinel surveillance data. We identified Africa and Asia as regions with studies showing high typhoid incidence while noting considerable variation of typhoid incidence in time and place, including in consecutive years at the same location. Overall, more recent studies reported lower typhoid incidence compared to years prior to 2000. We identified variation in the criteria for collecting a blood culture, and among multiplier studies we identified a lack of a standardization for the types of multipliers being used to estimate incidence. CONCLUSIONS Typhoid fever incidence remains high at many sites. Additional and more accurate typhoid incidence studies are needed to support country decisions about typhoid conjugate vaccine adoption. Standardization of multiplier types applied in multiplier studies is recommended.
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Affiliation(s)
| | - Chuen Yen Hong
- Centre for International Health, University of Otago, New Zealand
| | - John A Crump
- Centre for International Health, University of Otago, New Zealand
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18
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Medise BE, Soedjatmiko S, Rengganis I, Gunardi H, Sekartini R, Koesno S, Satari HI, Hadinegoro SR, Yang JS, Excler JL, Sahastrabuddhe S, Puspita M, Sari RM, Bachtiar NS. Six-month follow up of a randomized clinical trial-phase I study in Indonesian adults and children: Safety and immunogenicity of Salmonella typhi polysaccharide-diphtheria toxoid (Vi-DT) conjugate vaccine. PLoS One 2019; 14:e0211784. [PMID: 30759132 PMCID: PMC6373931 DOI: 10.1371/journal.pone.0211784] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/30/2018] [Indexed: 11/19/2022] Open
Abstract
Introduction There is a high global incidence of typhoid fever, with an annual mortality rate of 200,000 deaths. Typhoid fever also affects younger children, particularly in resource-limited settings in endemic countries. Typhoid vaccination is an important prevention tool against typhoid fever. However, the available polysaccharide typhoid vaccines are not recommended for children under 2 years of age. A new typhoid conjugate Vi-diphtheria toxoid (Vi-DT) vaccine has been developed for infant immunization. We aimed to define the safety and immunogenicity of the Vi-DT vaccine among adults and children in Indonesia. Methods An observational, blinded, comparative, randomized, phase I safety study in two age de-escalating cohorts was conducted in East Jakarta, Indonesia, from April 2017 to February 2018. We enrolled 100 healthy subjects in 2 age groups: adults and children (18–40 and 2–5 years old). These groups were randomized into study groups (Vi-DT vaccine), and comparator groups (Vi-polysaccharide (Vi-PS) vaccine and another additional vaccine) which was administered in 4 weeks apart. Subjects were followed up to six months. Result One hundred healthy adults and children subjects completed the study. The Vi-DT and Vi-PS vaccines showed no difference in terms of intensity of any immediate local and systemic events within 30 minutes post-vaccination. Overall, pain was the most common local reaction, and muscle pain was the most common systemic reaction in the first 72 hours. No serious adverse events were deemed related to vaccine administration. The first and second doses of the Vi-DT vaccine induced seroconversion and higher geometric mean titers (GMT) in all subjects compared to that of baseline. However, in terms of GMT, the second dose of Vi-DT did not induce a booster response. Conclusion The Vi-DT vaccine is safe and immunogenic in adults and children older than two years. A single dose of the vaccine is able to produce seroconversion and high GMT in all individuals.
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Affiliation(s)
- Bernie Endyarni Medise
- Department of Child Health, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
- * E-mail:
| | - Soedjatmiko Soedjatmiko
- Department of Child Health, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
| | - Iris Rengganis
- Department of Internal Medicine, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
| | - Hartono Gunardi
- Department of Child Health, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
| | - Rini Sekartini
- Department of Child Health, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
| | - Sukamto Koesno
- Department of Internal Medicine, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
| | - Hindra Irawan Satari
- Department of Child Health, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
| | - Sri Rezeki Hadinegoro
- Department of Child Health, Faculty of Medicine Universitas Indonesia, Dr. Cipto Mangunkusumo General National Hospital, Jakarta, Indonesia
| | - Jae Seung Yang
- International Vaccine Institute, Seoul, Republic of Korea
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19
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Church JA, Parker EP, Kirkpatrick BD, Grassly NC, Prendergast AJ. Interventions to improve oral vaccine performance: a systematic review and meta-analysis. Lancet Infect Dis 2019; 19:203-214. [PMID: 30712836 PMCID: PMC6353819 DOI: 10.1016/s1473-3099(18)30602-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/06/2018] [Accepted: 09/21/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Oral vaccines underperform in low-income and middle-income countries compared with in high-income countries. Whether interventions can improve oral vaccine performance is uncertain. METHODS We did a systematic review and meta-analysis of interventions designed to increase oral vaccine efficacy or immunogenicity. We searched Ovid-MEDLINE and Embase for trials published until Oct 23, 2017. Inclusion criteria for meta-analysis were two or more studies per intervention category and available seroconversion data. We did random-effects meta-analyses to produce summary relative risk (RR) estimates. This study is registered with PROSPERO (CRD42017060608). FINDINGS Of 2843 studies identified, 87 were eligible for qualitative synthesis and 66 for meta-analysis. 22 different interventions were assessed for oral poliovirus vaccine (OPV), oral rotavirus vaccine (RVV), oral cholera vaccine (OCV), and oral typhoid vaccines. There was generally high heterogeneity. Seroconversion to RVV was significantly increased by delaying the first RVV dose by 4 weeks (RR 1·37, 95% CI 1·16-1·62) and OPV seroconversion was increased with monovalent or bivalent OPV compared with trivalent OPV (RR 1·51, 95% CI 1·20-1·91). There was some evidence that separating RVV and OPV increased RVV seroconversion (RR 1·21, 95% CI 1·00-1·47) and that higher vaccine inoculum improved OCV seroconversion (RR 1·12, 95% CI 1·00-1·26). There was no evidence of effect for anthelmintics, antibiotics, probiotics, zinc, vitamin A, withholding breastfeeding, extra doses, or vaccine buffering. INTERPRETATION Most strategies did not improve oral vaccine performance. Delaying RVV and reducing OPV valence should be considered within immunisation programmes to reduce global enteric disease. New strategies to address the gap in oral vaccine efficacy are urgently required. FUNDING Wellcome Trust, Bill & Melinda Gates Foundation, UK Medical Research Council, and WHO Polio Research Committee.
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Affiliation(s)
- James A Church
- Centre for Genomics & Child Health, Blizard Institute, Queen Mary University of London, London, UK; Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe.
| | - Edward P Parker
- Department of Infectious Disease Epidemiology, St Mary's Campus, Imperial College London, London, UK
| | - Beth D Kirkpatrick
- Department of Microbiology and Molecular Genetics, Vaccine Testing Center, University of Vermont College of Medicine, Burlington, VT, USA
| | - Nicholas C Grassly
- Department of Infectious Disease Epidemiology, St Mary's Campus, Imperial College London, London, UK
| | - Andrew J Prendergast
- Centre for Genomics & Child Health, Blizard Institute, Queen Mary University of London, London, UK; Zvitambo Institute for Maternal and Child Health Research, Harare, Zimbabwe
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20
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Pennington SH, Ferreira DM, Caamaño-Gutiérrez E, Reiné J, Hewitt C, Hyder-Wright AD, Gordon SB, Gordon MA. Nonspecific effects of oral vaccination with live-attenuated Salmonella Typhi strain Ty21a. Sci Adv 2019; 5:eaau6849. [PMID: 30820452 PMCID: PMC6392763 DOI: 10.1126/sciadv.aau6849] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 01/22/2019] [Indexed: 05/16/2023]
Abstract
Epidemiological and immunological evidence suggests that some vaccines can reduce all-cause mortality through nonspecific changes made to innate immune cells. Here, we present the first data to describe the nonspecific immunological impact of oral vaccination with live-attenuated Salmonella Typhi strain Ty21a. We vaccinated healthy adults with Ty21a and assessed aspects of innate and adaptive immunity over the course of 6 months. Changes to monocyte phenotype/function were observed for at least 3 months. Changes to innate and adaptive immune cell cytokine production in response to stimulation with vaccine and unrelated nonvaccine antigens were observed over the 6-month study period. The changes that we have observed could influence susceptibility to infection through altered immune responses mounted to subsequently encountered pathogens. These changes could influence all-cause mortality.
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Affiliation(s)
- S. H. Pennington
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
- Corresponding author. (S.H.P.); (M.A.G.)
| | - D. M. Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - E. Caamaño-Gutiérrez
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, UK
- Computational Biology Facility, Institute of Integrative Biology, University of Liverpool, Liverpool, UK
| | - J. Reiné
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - C. Hewitt
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - A. D. Hyder-Wright
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - S. B. Gordon
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, P.O. Box 30096, Blantyre 3, Malawi
| | - M. A. Gordon
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, P.O. Box 30096, Blantyre 3, Malawi
- Corresponding author. (S.H.P.); (M.A.G.)
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21
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Domingos-Pereira S, Sathiyanadan K, La Rosa S, Polák L, Chevalier MF, Martel P, Hojeij R, Derré L, Haefliger JA, Jichlinski P, Nardelli-Haefliger D. Intravesical Ty21a Vaccine Promotes Dendritic Cells and T Cell-Mediated Tumor Regression in the MB49 Bladder Cancer Model. Cancer Immunol Res 2019; 7:621-629. [PMID: 30696629 DOI: 10.1158/2326-6066.cir-18-0671] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/28/2018] [Accepted: 01/25/2019] [Indexed: 11/16/2022]
Abstract
Preclinical data show that intravesical instillation of Ty21a/Vivotif, a commercial vaccine against typhoid fever, is an effective alternative option to standard Bacillus Calmette-Guérin (BCG) immunotherapy for non-muscle-invasive bladder cancer (NMIBC). Here, we characterized the inflammatory effects of Ty21a on the bladder and investigated the immune mechanisms underlying tumor regression toward the use of this bacterial vaccine in NMIBC patients. MB49 bladder tumor-bearing mice had significantly improved survival after intravesical instillations of Ty21a doses of 106 to 108 colony-forming units. By IHC and morphology, both BCG and Ty21a instillations were associated with bladder inflammation, which was decreased with the use of low, but effective doses of Ty21a. Flow-cytometry analysis showed a significant infiltration of T cells, natural killer (NK) cells, and myeloid cells, compared with controls, after a single dose of Ty21a, whereas this was only observed after multiple doses of BCG. The induced myeloid cells were predominantly neutrophils and Ly6C+CD103+ dendritic cells (DC), the latter being significantly more numerous after instillation of Ty21a than BCG. Ex vivo infection of human leukocytes with Ty21a, but not BCG, similarly significantly increased DC frequency. CD4+ and CD8+ T cells, but not NK cells nor neutrophils, were required for effective bladder tumor regression upon Ty21a treatment. Thus, the generation of antitumor adaptive immunity was identified as a key process underlying Ty21a-mediated treatment efficacy. Altogether, these results demonstrate mechanisms behind intravesical Ty21a therapy and suggest its potential as a safe and effective treatment for NMIBC patients.
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Affiliation(s)
| | - Karthik Sathiyanadan
- Department of Urology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Stefano La Rosa
- Service of Clinical Pathology, Institute of Pathology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Lenka Polák
- Department of Urology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Mathieu F Chevalier
- Department of Urology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Paul Martel
- Department of Urology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Rim Hojeij
- Department of Urology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Laurent Derré
- Department of Urology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | | | - Patrice Jichlinski
- Department of Urology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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Affiliation(s)
- Florian Marks
- International Vaccine Institute, Seoul 08826, South Korea; The Department of Medicine, University of Cambridge, Cambridge, UK.
| | - Jerome H Kim
- International Vaccine Institute, Seoul 08826, South Korea
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23
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Barac R, Als D, Radhakrishnan A, Gaffey MF, Bhutta ZA, Barwick M. Implementation of Interventions for the Control of Typhoid Fever in Low- and Middle-Income Countries. Am J Trop Med Hyg 2018; 99:79-88. [PMID: 30047365 PMCID: PMC6128369 DOI: 10.4269/ajtmh.18-0110] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/05/2018] [Indexed: 01/12/2023] Open
Abstract
Past research has focused on typhoid fever surveillance with little attention to implementation methods or effectiveness of control interventions. This study purposefully sampled key informants working in public health in Chile, India, Pakistan, Bangladesh, Thailand, Vietnam, South Africa, and Nigeria to 1) scope typhoid-relevant interventions implemented between 1990 and 2015 and 2) explore contextual factors perceived to be associated with their implementation, based on the Consolidated Framework for Implementation Research (CFIR). We used a mixed methods design and collected quantitative data (CFIR questionnaire) and qualitative data (interviews with 34 public health experts). Interview data were analyzed using a deductive qualitative content analysis and summary descriptive statistics are provided for the CFIR data. Despite relatively few typhoid-specific interventions reportedly implemented in these countries, interventions for diarrheal disease control and regulations for food safety and food handlers were common. Most countries implemented agricultural and sewage treatment practices, yet few addressed the control of antibiotic medication. Several contextual factors were perceived to have influenced the implementation of typhoid interventions, either as enablers (e.g., economic development) or barriers (e.g., limited resources and habitual behaviors). Consolidated Framework for Implementation Research factors rated as important in the implementation of typhoid interventions were remarkably consistent across countries. The findings provide a snapshot of typhoid-relevant interventions implemented over 25 years and highlight factors associated with implementation success from the perspective of a sample of key informants. These findings can inform systematic investigations of the implementation of typhoid control interventions and contribute to a better understanding of the direct effects of implementation efforts.
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Affiliation(s)
- Raluca Barac
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Research Institute, The Hospital for Sick Children, Toronto, Canada
| | - Daina Als
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | | | - Michelle F. Gaffey
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
| | - Zulfiqar A. Bhutta
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
- Center of Excellence in Women and Child Health, The Aga Khan University, Karachi, Pakistan
| | - Melanie Barwick
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
- Research Institute, The Hospital for Sick Children, Toronto, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
- Department of Psychiatry, University of Toronto, Toronto, Canada
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24
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Pennington SH, Ferreira DM, Reiné J, Nyirenda TS, Thompson AL, Hancock CA, Wright AD, Gordon SB, Gordon MA. Longevity of duodenal and peripheral T-cell and humoral responses to live-attenuated Salmonella Typhi strain Ty21a. Vaccine 2018; 36:4725-4733. [PMID: 29958737 PMCID: PMC6041722 DOI: 10.1016/j.vaccine.2018.05.114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 05/08/2018] [Accepted: 05/31/2018] [Indexed: 12/26/2022]
Abstract
BACKGROUND We have previously demonstrated that polyfunctional Ty21a-responsive CD4+ and CD8+ T cells are generated at the duodenal mucosa 18 days following vaccination with live-attenuated S. Typhi (Ty21a). The longevity of cellular responses has been assessed in peripheral blood, but persistence of duodenal responses is unknown. METHODS We vaccinated eight healthy adults with Ty21a. Peripheral blood and duodenal samples were acquired after a median of 1.5 years (ranging from 1.1 to 3.7 years) following vaccination. Cellular responses were assessed in peripheral blood and at the duodenal mucosa by flow cytometry. Levels of IgG and IgA were also assessed in peripheral blood by enzyme-linked immunosorbent assay. RESULTS No T-cell responses were observed at the duodenal mucosa, but CD4+ T-cell responses to Ty21a and FliC were observed in peripheral blood. Peripheral anti-lipopolysaccharide IgG and IgA responses were also observed. Early immunoglobulin responses were not associated with the persistence of long-term cellular immune responses. CONCLUSIONS Early T-cell responses which we have previously observed at the duodenal mucosa 18 days following oral vaccination with Ty21a could not be detected at a median of 1.5 years. Peripheral responses were observed at this time. Immunoglobulin responses observed shortly after vaccination were not associated with cellular immune responses at 1.5 years, suggesting that the persistence of cellular immunity is not associated with the strength of the initial humoral response to vaccination.
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Affiliation(s)
- Shaun H Pennington
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, UK; Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK
| | - Daniela M Ferreira
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK
| | - Jesús Reiné
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK
| | - Tonney S Nyirenda
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Queen Elizabeth Central Hospital, Malawi
| | - Ameeka L Thompson
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, UK; Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK
| | - Carole A Hancock
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK
| | - Angela D Wright
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK
| | - Stephen B Gordon
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, UK; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Queen Elizabeth Central Hospital, Malawi
| | - Melita A Gordon
- Department of Clinical Infection, Microbiology and Immunology, Institute of Infection and Global Health, University of Liverpool, UK; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, College of Medicine, Queen Elizabeth Central Hospital, Malawi.
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Zhang Y, Brady A, Jones C, Song Y, Darton TC, Jones C, Blohmke CJ, Pollard AJ, Magder LS, Fasano A, Sztein MB, Fraser CM. Compositional and Functional Differences in the Human Gut Microbiome Correlate with Clinical Outcome following Infection with Wild-Type Salmonella enterica Serovar Typhi. mBio 2018; 9:e00686-18. [PMID: 29739901 PMCID: PMC5941076 DOI: 10.1128/mbio.00686-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 01/09/2023] Open
Abstract
Insights into disease susceptibility as well as the efficacy of vaccines against typhoid and other enteric pathogens may be informed by better understanding the relationship between the effector immune response and the gut microbiota. In the present study, we characterized the composition (16S rRNA gene profiling) and function (RNA sequencing [RNA-seq]) of the gut microbiota following immunization and subsequent exposure to wild-type Salmonella enterica serovar Typhi in a human challenge model to further investigate the central hypothesis that clinical outcomes may be linked to the gut microbiota. Metatranscriptome analysis of longitudinal stool samples collected from study subjects revealed two stable patterns of gene expression for the human gut microbiota, dominated by transcripts from either Methanobrevibacter or a diverse representation of genera in the Firmicutes phylum. Immunization with one of two live oral attenuated vaccines against S. Typhi had minimal effects on the composition or function of the gut microbiota. It was observed that subjects harboring the methanogen-dominated transcriptome community at baseline displayed a lower risk of developing symptoms of typhoid following challenge with wild-type S. Typhi. Furthermore, genes encoding antioxidant proteins, metal homeostasis and transport proteins, and heat shock proteins were expressed at a higher level at baseline or after challenge with S. Typhi in subjects who did not develop symptoms of typhoid. These data suggest that functional differences relating to redox potential and ion homeostasis in the gut microbiota may impact clinical outcomes following exposure to wild-type S. Typhi.IMPORTANCES. Typhi is a significant cause of systemic febrile morbidity in settings with poor sanitation and limited access to clean water. It has been demonstrated that the human gut microbiota can influence mucosal immune responses, but there is little information available on the impact of the human gut microbiota on clinical outcomes following exposure to enteric pathogens. Here, we describe differences in the composition and function of the gut microbiota in healthy adult volunteers enrolled in a typhoid vaccine trial and report that these differences are associated with host susceptibility to or protection from typhoid after challenge with wild-type S Typhi. Our observations have important implications in interpreting the efficacy of oral attenuated vaccines against enteric pathogens in diverse populations.
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Affiliation(s)
- Yan Zhang
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Arthur Brady
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Cheron Jones
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yang Song
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Thomas C Darton
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Christoph J Blohmke
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom
| | - Laurence S Magder
- Department of Epidemiology and Preventive Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Alessio Fasano
- Department of Pediatrics, Mucosal Immunology and Biology Research Center, Harvard Medical School, Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Marcelo B Sztein
- Department of Pediatrics, Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Claire M Fraser
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Abstract
Objective In 2010, candid advice concerning the low rate of typhoid vaccination among Japanese travelers was received from Nepal. Recently, progressive Japanese travel clinics have encouraged Japanese travelers to be vaccinated against typhoid fever in conjunction with officially approved vaccines, such as hepatitis A vaccine. We herein report the status of typhoid vaccinations for Japanese travelers to the most endemic area (South Asia) and describe the factors associated with compliance. Methods In the travel clinic at Kurume University Hospital, we used the following criteria to retrospectively extract the records of new pre-travel Japanese clients between January 2011 and March 2015: hepatitis A vaccine administered, traveling to South Asian countries, and ≥2 years of age. We first summarized the participants and then divided them into typhoid-vaccinated and typhoid non-vaccinated groups for a comparative analysis. Results This study included 160 clients. A majority (70.0%) of these clients traveled for business. The duration of trips was long (≥1 month) (75.0%), and India was a popular destination (90.6%). A comparative study between the vaccinated group (n=122) and the non-vaccinated group (n=38) revealed that the two factors most positively associated with typhoid vaccination were business trips [adjusted odds ratio (aOR) 3.59, 95% confidence interval (CI) 1.42-9.06] and coverage by a company/organization payment plan (aOR 7.14, 95% CI 2.67-20.3). Conclusion The trend toward typhoid vaccination among Japanese travelers to South Asia with pre-travel consultation is correlated with business trips and coverage by a company/organization payment plan. If problems concerning the cost of vaccines were resolved, more travelers would request typhoid vaccination.
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Affiliation(s)
- Kenichiro Yaita
- Department of Infection Control and Prevention, Kurume University School of Medicine, Japan
| | - Koji Yahara
- Department of Bacteriology II, National Institute of Infectious Diseases, Japan
| | - Nobuyuki Hamada
- Department of Infection Control and Prevention, Kurume University School of Medicine, Japan
| | - Yoshiro Sakai
- Department of Infection Control and Prevention, Kurume University School of Medicine, Japan
- Department of Pharmacy, Kurume University Hospital, Japan
| | - Jun Iwahashi
- Department of Infection Control and Prevention, Kurume University School of Medicine, Japan
| | - Kenji Masunaga
- Department of Infection Control and Prevention, Kurume University School of Medicine, Japan
| | - Hiroshi Watanabe
- Department of Infection Control and Prevention, Kurume University School of Medicine, Japan
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Immunization and Vaccine-related Implementation Research Advisory Committee (IVIR-AC): summary of conclusions and recommendations, 20–22 September 2017. Wkly Epidemiol Rec 2018; 93:1-7. [PMID: 29303231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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Ni Y, Springer MJ, Guo J, Finger-Baker I, Wilson JP, Cobb RR, Turner D, Tizard I. Development of a synthetic Vi polysaccharide vaccine for typhoid fever. Vaccine 2017; 35:7121-7126. [PMID: 29150208 PMCID: PMC5754192 DOI: 10.1016/j.vaccine.2017.10.081] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 10/15/2017] [Accepted: 10/29/2017] [Indexed: 12/16/2022]
Abstract
Typhoid fever remains a serious public health problem with a high impact on toddlers and young children. Vaccines against the Vi capsular polysaccharide are efficacious against typhoid fever demonstrating that antibodies against Vi confer protection. The currently licensed Vi typhoid vaccines have however limited efficacy and are manufactured by a complex process from wild-type bacteria. Due to these inherent issues with the current vaccines, an alternative vaccine based on an O-acetylated high molecular weight (HMW) polygalacturonic acid (GelSite-OAc™) was generated. The HMW polygalacturonic acid shares the same backbone as the Vi polysaccharide of Salmonella Typhi. The GelSite-OAc™ has a high molecular weight (>1 × 106 Da) and a high degree of O-acetylation (DOAc) (>5 μmole/mg), both exceeding the potency specifications of the current Vi vaccine. Studies in Balb/c mice demonstrated that GelSite-OAc™ was highly immunogenic, inducing a strong antigen-specific antibody response in a DOAc- and dose-dependent manner which was comparable to or higher than those induced by the licensed Vi vaccine. Importantly, the GelSite-OAc™ was shown to be fully protective in mice against lethal challenge with Salmonella Typhi. Furthermore, the GelSite-OAc™ demonstrated a boosting effect or memory response, exhibiting a >2-fold increase in antibody levels upon the second immunization with either GelSite-OAc™ or the Vi vaccine. This novel boosting effect is unique among polysaccharide antigens and potentially makes GelSite-OAc™ effective in people under 2 years old. Together these results suggest that the GelSite-OAc™ could be a highly effective vaccine against Salmonella Typhi.
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MESH Headings
- Acetylation
- Animals
- Antibodies, Bacterial/blood
- Antibody Formation/immunology
- Disease Models, Animal
- Immunization, Secondary
- Immunogenicity, Vaccine
- Immunoglobulin G/blood
- Immunologic Memory
- Mice
- Pectins/administration & dosage
- Pectins/chemistry
- Pectins/immunology
- Polysaccharides, Bacterial/administration & dosage
- Polysaccharides, Bacterial/chemistry
- Polysaccharides, Bacterial/immunology
- Salmonella typhi/immunology
- Typhoid Fever/immunology
- Typhoid Fever/microbiology
- Typhoid Fever/prevention & control
- Typhoid-Paratyphoid Vaccines/administration & dosage
- Typhoid-Paratyphoid Vaccines/chemistry
- Typhoid-Paratyphoid Vaccines/immunology
- Vaccines, Synthetic/administration & dosage
- Vaccines, Synthetic/chemistry
- Vaccines, Synthetic/immunology
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Affiliation(s)
- Yawei Ni
- Research and Development, Nanotherapeutics, Inc., Alachua, FL, USA.
| | | | - Jianhua Guo
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | | | - James P Wilson
- Research and Development, Nanotherapeutics, Inc., Alachua, FL, USA
| | - Ronald R Cobb
- Research and Development, Nanotherapeutics, Inc., Alachua, FL, USA
| | - Debra Turner
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Ian Tizard
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, USA
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Salman M, St Michael F, Ali A, Jabbar A, Cairns C, Hayes AC, Rahman M, Iqbal M, Haque A, Cox AD. First characterization of immunogenic conjugates of Vi negative Salmonella Typhi O-specific polysaccharides with rEPA protein for vaccine development. J Immunol Methods 2017; 450:27-33. [PMID: 28735760 DOI: 10.1016/j.jim.2017.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
Efficacious typhoid vaccines for young children will significantly reduce the disease burden in developing world. The Vi polysaccharide based conjugate vaccines (Vi-rEPA) against Salmonella Typhi Vi positive strains has shown high efficacy but may be ineffective against Vi negative S. Typhi. In this study, for the first time, we report the synthesis and evaluation of polysaccharide-protein conjugates of Vi negative S. Typhi as potential vaccine candidates. Four different conjugates were synthesized using recombinant exoprotein A of Pseudomonas aeruginosa (rEPA) and human serum albumin (HSA) as the carrier proteins, using either direct reductive amination or an intermediate linker molecule, adipic acid dihydrazide (ADH). Upon injection into mice, a significantly higher antibody titer was observed in mice administrated with conjugate-1 (OSP-HSA) (P=0.0001) and conjugate 2 (OSP-rEPA) (P≤0.0001) as compared to OSP alone. In contrast, the antibody titer elicited by conjugate 3 (OSPADH-HSA) and conjugate 4 (OSPADH-rEPA) were insignificant (P=0.1684 and P=0.3794, respectively). We conclude that reductive amination is the superior method to prepare the S. Typhi OSP glycoconjugate. Moreover, rEPA was a better carrier protein than HSA. Thus OSP-rEPA conjugate seems to be efficacious typhoid vaccines candidate, it may be evaluated further and recommended for the clinical trials.
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Affiliation(s)
- M Salman
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Canada; Health Biotechnology Division, National Institute for Biotechnology, Faisalabad, Pakistan; Department of Microbiology and Biotechnology, Abasyn University, Peshawar, Pakistan.
| | - F St Michael
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Canada
| | - A Ali
- Health Biotechnology Division, National Institute for Biotechnology, Faisalabad, Pakistan
| | - A Jabbar
- Department of Biotechnology, Mirpur University of Science & Technology (MUST), Mirpur, AJK, Pakistan
| | - C Cairns
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Canada
| | - A C Hayes
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Canada
| | - M Rahman
- Health Biotechnology Division, National Institute for Biotechnology, Faisalabad, Pakistan
| | - M Iqbal
- Health Biotechnology Division, National Institute for Biotechnology, Faisalabad, Pakistan
| | - A Haque
- Faculty of Life Sciences, University of Faisalabad, Faisalabad, Pakistan
| | - A D Cox
- Vaccine Program, Human Health Therapeutics Portfolio, National Research Council, Ottawa, Canada.
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Saha S, Islam M, Uddin MJ, Saha S, Das RC, Baqui AH, Santosham M, Black RE, Luby SP, Saha SK. Integration of enteric fever surveillance into the WHO-coordinated Invasive Bacterial-Vaccine Preventable Diseases (IB-VPD) platform: A low cost approach to track an increasingly important disease. PLoS Negl Trop Dis 2017; 11:e0005999. [PMID: 29073137 PMCID: PMC5658195 DOI: 10.1371/journal.pntd.0005999] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/28/2017] [Indexed: 01/07/2023] Open
Abstract
Background Lack of surveillance systems and accurate data impede evidence-based decisions on treatment and prevention of enteric fever, caused by Salmonella Typhi/Paratyphi. The WHO coordinates a global Invasive Bacterial–Vaccine Preventable Diseases (IB-VPD) surveillance network but does not monitor enteric fever. We evaluated the feasibility and sustainability of integrating enteric fever surveillance into the ongoing IB-VPD platform. Methodologies The IB-VPD surveillance system uses WHO definitions to enroll 2–59 month children hospitalized with possible pneumonia, sepsis or meningitis. We expanded this surveillance system to additionally capture suspect enteric fever cases during 2012–2016, in two WHO sentinel hospitals of Bangladesh, by adding inclusion criteria of fever ≥102°F for ≥3 days, irrespective of other manifestations. Culture-positive enteric fever cases from in-patient departments (IPD) detected in the hospital laboratories but missed by the expanded surveillance, were also enrolled to assess completion. Costs for this integration were calculated for the additional personnel and resources required. Principal findings In the IB-VPD surveillance, 5,185 cases were enrolled; 3% (N = 171/5185) were positive for microbiological growth, of which 55% (94/171) were culture-confirmed cases of enteric fever (85 Typhi and 9 Paratyphi A). The added inclusion criteria for enteric fever enrolled an additional 1,699 cases; 22% (358/1699) were positive, of which 85% (349/358) were enteric fever cases (305 Typhi and 44 Paratyphi A). Laboratory surveillance of in-patients of all ages enrolled 311 additional enteric fever cases (263 Typhi and 48 Paratyphi A); 9% (28/311) were 2–59 m and 91% (283/311) >59 m. Altogether, 754 (94+349+311) culture-confirmed enteric fever cases were found, of which 471 were 2–59 m. Of these 471 cases, 94% (443/471) were identified through the hospital surveillances and 6% (28/471) through laboratory results. Twenty-three percent (170/754) of all cases were children <2 years. Additional cost for the integration was USD 44,974/year, a 27% increase to the IB-VPD annual expenditure. Conclusion In a setting where enteric disease is a substantial public health problem, we could integrate enteric fever surveillance into the standard IB-VPD surveillance platform at a modest cost. Typhoid/paratyphoid fever imposes a major global burden, specifically in low-and-middle-income countries (LMICs). However, it is challenging to implement evidence-based decisions for treatment and prevention because of lack of data from comprehensive surveillance systems, which are often expensive and difficult to sustain. The WHO has established a global surveillance program called “Invasive Bacterial–Vaccine Preventable Diseases (IB-VPD) Surveillance” to capture sepsis, meningitis and pneumonia in under-five children in many LMICs. Data generated by this program have facilitated introduction of live-saving vaccines and development of treatment strategies. However, the program does not include typhoid/paratyphoid surveillance. We tested the feasibility and sustainability of integrating typhoid/paratyphoid surveillance into this program in two leading children’s hospitals in Bangladesh. By monitoring all patients with signs of typhoid/paratyphoid, we captured 471 laboratory-confirmed episodes in under-five children between Jan 2012 and Dec 2016. Blood culture results from all in-patients revealed that the proposed expanded surveillance captures 94% of hospitalized typhoid/paratyphoid cases. Thirty-six percent (170/471) of 2–59 m cases were in children <2 years. Overall, age distribution and antibiotic resistance patterns were consistent with data generated from larger, expensive and typhoid-specific surveillance programs in the region, adding credence to the proposed integration. Adding typhoid/paratyphoid surveillance to an established invasive disease surveillance platform took advantage of existing infrastructure and resources and as such was easy and cost-effective to implement. We recommend that WHO considers similar integration in other countries; data generated from such surveillances will help countries make evidence-based decisions on introduction of upcoming vaccines and prepare for impact studies.
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Affiliation(s)
- Senjuti Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
| | - Maksuda Islam
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
| | - Mohammad J. Uddin
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
| | - Shampa Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
| | - Rajib C. Das
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
| | - Abdullah H. Baqui
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Mathuram Santosham
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Robert E. Black
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Stephen P. Luby
- Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, Stanford, CA, United States of America
| | - Samir K. Saha
- Child Health Research Foundation, Department of Microbiology, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
- Bangladesh Institute of Child Health, Dhaka Shishu (Children) Hospital, Dhaka, Bangladesh
- * E-mail:
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Antillón M, Bilcke J, Paltiel AD, Pitzer VE. Cost-effectiveness analysis of typhoid conjugate vaccines in five endemic low- and middle-income settings. Vaccine 2017; 35:3506-3514. [PMID: 28527687 PMCID: PMC5462484 DOI: 10.1016/j.vaccine.2017.05.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 04/28/2017] [Accepted: 05/01/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND Typhoid fever remains endemic in low- and middle-income countries. Programmatic use of existing vaccines is limited, but upcoming typhoid conjugate vaccines (TCVs) could warrant wider use. We evaluated the cost-effectiveness of five TCV delivery strategies in three urban areas (Delhi and Kolkata, India and Nairobi, Kenya) and two rural settings (Lwak, Kenya and Dong Thap, Vietnam) with varying incidence. METHODS AND FINDINGS We evaluated routine infant vaccination with and without catch-up campaigns among older individuals. We used a dynamic model of typhoid transmission to simulate cases, hospitalizations, deaths, disability-adjusted life-years (DALY) lost, treatment and intervention costs. We estimated cost-effectiveness (in terms of cost in international dollars (I$) per DALY averted) from the healthcare payer perspective, and assessed how it was influenced by uncertain model parameters. Compared to no vaccination, routine infant vaccination at I$1/dose was cost-saving in Delhi and Dong Thap, "very cost-effective" in Kolkata and Nairobi, and "cost-effective" in Lwak according to World Health Organization thresholds. However, routine vaccination was not the optimal strategy compared to strategies that included a catch-up campaign, which yielded the highest probability of being cost-saving in Delhi and Dong Thap and were most likely to provide a return on investment above a willingness-to-pay threshold of I$1440 in Kolkata, I$2300 in Nairobi, and I$5360 in Lwak. Vaccine price impacted the optimal strategy, and the number of doses required and rate of hospitalization were the primary sources of uncertainty. CONCLUSION Routine vaccination with TCV would be cost-effective in most settings, and additional one-time catch-up campaigns would also be economically justified.
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Affiliation(s)
- Marina Antillón
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520-8034, USA.
| | - Joke Bilcke
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520-8034, USA; Center for Health Economics Research and Modeling Infectious Diseases, University of Antwerp, Belgium
| | - A David Paltiel
- Department of Health Policy and Management, Yale School of Public Health, New Haven, CT 06520-8034, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06520-8034, USA.
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Immunization and Vaccine-related Implementation Research Advisory Committee (IVIR-AC): summary of conclusions and recommendations, 1–2 February 2017 meeting. Wkly Epidemiol Rec 2017; 92:181-8. [PMID: 28413874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
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Porter CK, Sorrell T, Mitra I, Riddle MS. Vaccination of active component US military personnel against Salmonella Typhi. Vaccine 2017; 35:1742-1748. [PMID: 28268075 DOI: 10.1016/j.vaccine.2017.02.050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 01/26/2017] [Accepted: 02/23/2017] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Vaccination against Salmonella Typhi is one of the leading public health interventions reducing the risk of typhoid fever. There are two available licensed vaccines, Vivotif, oral live-attenuated, and Typhim Vi, intramuscular Vi capsular polysaccharide. The US military is a high risk travel population commonly vaccinated for S. Typhi. We describe the use of S. Typhi vaccination in this population and the acute reactogenicity profile of these vaccines. METHODS Data were obtained from the Defense Medical Surveillance System and vaccination identified between 1998 and 2011 from vaccination codes. Clinical outcomes were assessed for four weeks post vaccination. Adverse event rates and odds ratios were estimated across the two vaccine types. RESULTS A total of 1.9million predominately male military personnel received 3.6 million S. Typhi vaccinations with 94.3% of vaccinees receiving the Vi capsule vaccine though variability in the vaccine administered was observed. Receipt of other vaccinations in the 6months surrounding the S. Typhi vaccine was common. Rates of nausea (195 per 100,000 vaccinations), headache (13 per 100,000 vaccinations) and fever (40 per 100,000 vaccinations) were significantly higher following Vi capsule vaccination compared to receipt of Vivotif (130, 2, 10 per 100,000 vaccinations, respectively). In contrast the rates of rash and non-infectious diarrhea (186 and 426 per 100,000 vaccinations, respectively) were increased in those receiving Vivotif compared to the Vi capsule vaccine. DISCUSSION The US military is a major consumer of S. Typhi vaccines. The parenterally administered vaccine appears to be more amenable, though we were limited in our ability to assess the reasons for its higher usage. While we observed a higher rate of several adverse events in subjects receiving the intramuscular vaccination, the overall rate of these events was low. Future studies assessing more long-term health outcomes are warranted.
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Affiliation(s)
- Chad K Porter
- Naval Medical Research Center, Enteric Diseases Department, Silver Spring, MD, United States.
| | - Tia Sorrell
- Naval Medical Research Center, Enteric Diseases Department, Silver Spring, MD, United States; Henry M. Jackson Foundation, Rockville, MD, United States
| | - Indrani Mitra
- Uniformed Services University, Infectious Disease Clinical Research Program, Bethesda, MD, United States
| | - Mark S Riddle
- Naval Medical Research Center, Enteric Diseases Department, Silver Spring, MD, United States
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Dyson ZA, Thanh DP, Bodhidatta L, Mason CJ, Srijan A, Rabaa MA, Vinh PV, Thanh TH, Thwaites GE, Baker S, Holt KE. Whole Genome Sequence Analysis of Salmonella Typhi Isolated in Thailand before and after the Introduction of a National Immunization Program. PLoS Negl Trop Dis 2017; 11:e0005274. [PMID: 28060810 PMCID: PMC5245908 DOI: 10.1371/journal.pntd.0005274] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 01/19/2017] [Accepted: 12/20/2016] [Indexed: 12/31/2022] Open
Abstract
Vaccines against Salmonella Typhi, the causative agent of typhoid fever, are commonly used by travellers, however, there are few examples of national immunization programs in endemic areas. There is therefore a paucity of data on the impact of typhoid immunization programs on localised populations of S. Typhi. Here we have used whole genome sequencing (WGS) to characterise 44 historical bacterial isolates collected before and after a national typhoid immunization program that was implemented in Thailand in 1977 in response to a large outbreak; the program was highly effective in reducing typhoid case numbers. Thai isolates were highly diverse, including 10 distinct phylogenetic lineages or genotypes. Novel prophage and plasmids were also detected, including examples that were previously only reported in Shigella sonnei and Escherichia coli. The majority of S. Typhi genotypes observed prior to the immunization program were not observed following it. Post-vaccine era isolates were more closely related to S. Typhi isolated from neighbouring countries than to earlier Thai isolates, providing no evidence for the local persistence of endemic S. Typhi following the national immunization program. Rather, later cases of typhoid appeared to be caused by the occasional importation of common genotypes from neighbouring Vietnam, Laos, and Cambodia. These data show the value of WGS in understanding the impacts of vaccination on pathogen populations and provide support for the proposal that large-scale typhoid immunization programs in endemic areas could result in lasting local disease elimination, although larger prospective studies are needed to test this directly. Typhoid fever is a systemic infection caused by the bacterium Salmonella Typhi. Typhoid fever is associated with inadequate hygiene in low-income settings and a lack of sanitation infrastructure. A sustained outbreak of typhoid fever occurred in Thailand in the 1970s, which peaked in 1975–1976. In response to this typhoid fever outbreak the government of Thailand initiated an immunization program, which resulted in a dramatic reduction in the number of typhoid cases in Thailand. To better understand the population of S. Typhi circulating in Thailand at this time, as well as the impact of the immunization program on the pathogen population, we sequenced the genomes of 44 S. Typhi obtained from hospitals in Thailand before and after the immunization program. The genome sequences showed that isolates of S. Typhi bacteria isolated from post-immunization era typhoid cases were likely imported from neighbouring countries, rather than strains that have persisted in Thailand throughout the immunization period. Our work provides the first historical insights into S. Typhi in Thailand during the 1970s, and provides a model for the impact of immunization on S. Typhi populations.
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Affiliation(s)
- Zoe A. Dyson
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- * E-mail: (KEH); (ZAD)
| | - Duy Pham Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Ladaporn Bodhidatta
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Carl Jeffries Mason
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Apichai Srijan
- Department of Enteric Diseases, Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Maia A. Rabaa
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Phat Voong Vinh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Tuyen Ha Thanh
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Guy E. Thwaites
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Kathryn E. Holt
- Centre for Systems Genomics, University of Melbourne, Parkville, Victoria, Australia
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
- * E-mail: (KEH); (ZAD)
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Rathod KS, Kapil V, Velmurugan S, Khambata RS, Siddique U, Khan S, Van Eijl S, Gee LC, Bansal J, Pitrola K, Shaw C, D’Acquisto F, Colas RA, Marelli-Berg F, Dalli J, Ahluwalia A. Accelerated resolution of inflammation underlies sex differences in inflammatory responses in humans. J Clin Invest 2017; 127:169-182. [PMID: 27893465 PMCID: PMC5199722 DOI: 10.1172/jci89429] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/17/2016] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Cardiovascular disease occurs at lower incidence in premenopausal females compared with age-matched males. This variation may be linked to sex differences in inflammation. We prospectively investigated whether inflammation and components of the inflammatory response are altered in females compared with males. METHODS We performed 2 clinical studies in healthy volunteers. In 12 men and 12 women, we assessed systemic inflammatory markers and vascular function using brachial artery flow-mediated dilation (FMD). In a further 8 volunteers of each sex, we assessed FMD response to glyceryl trinitrate (GTN) at baseline and at 8 hours and 32 hours after typhoid vaccine. In a separate study in 16 men and 16 women, we measured inflammatory exudate mediators and cellular recruitment in cantharidin-induced skin blisters at 24 and 72 hours. RESULTS Typhoid vaccine induced mild systemic inflammation at 8 hours, reflected by increased white cell count in both sexes. Although neutrophil numbers at baseline and 8 hours were greater in females, the neutrophils were less activated. Systemic inflammation caused a decrease in FMD in males, but an increase in females, at 8 hours. In contrast, GTN response was not altered in either sex after vaccine. At 24 hours, cantharidin formed blisters of similar volume in both sexes; however, at 72 hours, blisters had only resolved in females. Monocyte and leukocyte counts were reduced, and the activation state of all major leukocytes was lower, in blisters of females. This was associated with enhanced levels of the resolving lipids, particularly D-resolvin. CONCLUSIONS Our findings suggest that female sex protects against systemic inflammation-induced endothelial dysfunction. This effect is likely due to accelerated resolution of inflammation compared with males, specifically via neutrophils, mediated by an elevation of the D-resolvin pathway. TRIAL REGISTRATION ClinicalTrials.gov NCT01582321 and NRES: City Road and Hampstead Ethics Committee: 11/LO/2038. FUNDING The authors were funded by multiple sources, including the National Institute for Health Research, the British Heart Foundation, and the European Research Council.
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Darton TC, Jones C, Blohmke CJ, Waddington CS, Zhou L, Peters A, Haworth K, Sie R, Green CA, Jeppesen CA, Moore M, Thompson BAV, John T, Kingsley RA, Yu LM, Voysey M, Hindle Z, Lockhart S, Sztein MB, Dougan G, Angus B, Levine MM, Pollard AJ. Using a Human Challenge Model of Infection to Measure Vaccine Efficacy: A Randomised, Controlled Trial Comparing the Typhoid Vaccines M01ZH09 with Placebo and Ty21a. PLoS Negl Trop Dis 2016; 10:e0004926. [PMID: 27533046 PMCID: PMC4988630 DOI: 10.1371/journal.pntd.0004926] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 07/25/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Typhoid persists as a major cause of global morbidity. While several licensed vaccines to prevent typhoid are available, they are of only moderate efficacy and unsuitable for use in children less than two years of age. Development of new efficacious vaccines is complicated by the human host-restriction of Salmonella enterica serovar Typhi (S. Typhi) and lack of clear correlates of protection. In this study, we aimed to evaluate the protective efficacy of a single dose of the oral vaccine candidate, M01ZH09, in susceptible volunteers by direct typhoid challenge. METHODS AND FINDINGS We performed a randomised, double-blind, placebo-controlled trial in healthy adult participants at a single centre in Oxford (UK). Participants were allocated to receive one dose of double-blinded M01ZH09 or placebo or 3-doses of open-label Ty21a. Twenty-eight days after vaccination, participants were challenged with 104CFU S. Typhi Quailes strain. The efficacy of M01ZH09 compared with placebo (primary outcome) was assessed as the percentage of participants reaching pre-defined endpoints constituting typhoid diagnosis (fever and/or bacteraemia) during the 14 days after challenge. Ninety-nine participants were randomised to receive M01ZH09 (n = 33), placebo (n = 33) or 3-doses of Ty21a (n = 33). After challenge, typhoid was diagnosed in 18/31 (58.1% [95% CI 39.1 to 75.5]) M01ZH09, 20/30 (66.7% [47.2 to 87.2]) placebo, and 13/30 (43.3% [25.5 to 62.6]) Ty21a vaccine recipients. Vaccine efficacy (VE) for one dose of M01ZH09 was 13% [95% CI -29 to 41] and 35% [-5 to 60] for 3-doses of Ty21a. Retrospective multivariable analyses demonstrated that pre-existing anti-Vi antibody significantly reduced susceptibility to infection after challenge; a 1 log increase in anti-Vi IgG resulting in a 71% decrease in the hazard ratio of typhoid diagnosis ([95% CI 30 to 88%], p = 0.006) during the 14 day challenge period. Limitations to the study included the requirement to limit the challenge period prior to treatment to 2 weeks, the intensity of the study procedures and the high challenge dose used resulting in a stringent model. CONCLUSIONS Despite successfully demonstrating the use of a human challenge study to directly evaluate vaccine efficacy, a single-dose M01ZH09 failed to demonstrate significant protection after challenge with virulent Salmonella Typhi in this model. Anti-Vi antibody detected prior to vaccination played a major role in outcome after challenge. TRIAL REGISTRATION ClinicalTrials.gov (NCT01405521) and EudraCT (number 2011-000381-35).
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Affiliation(s)
- Thomas C. Darton
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Claire Jones
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Christoph J. Blohmke
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Claire S. Waddington
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Liqing Zhou
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Anna Peters
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Kathryn Haworth
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Rebecca Sie
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Christopher A. Green
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Catherine A. Jeppesen
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Maria Moore
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Ben A. V. Thompson
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
| | - Tessa John
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
| | - Robert A. Kingsley
- Microbial Pathogenesis Group, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Ly-Mee Yu
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
| | - Merryn Voysey
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, United Kingdom
| | - Zoe Hindle
- Emergent Product Development UK Ltd, Emergent BioSolutions, Wokingham, United Kingdom
| | - Stephen Lockhart
- Emergent Product Development UK Ltd, Emergent BioSolutions, Wokingham, United Kingdom
| | - Marcelo B. Sztein
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Gordon Dougan
- Microbial Pathogenesis Group, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Brian Angus
- Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Myron M. Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Andrew J. Pollard
- Oxford Vaccine Group, Department of Paediatrics, and the NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom
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Khan MI, Katrinak C, Freeman A, Franco-Paredes C. Enteric Fever and Invasive Nontyphoidal Salmonellosis--9th International Conference on Typhoid and Invasive NTS Disease, Bali, Indonesia, April 30-May 3, 2015. Emerg Infect Dis 2016; 22:e151463. [PMID: 27366797 PMCID: PMC4806947 DOI: 10.3201/eid2204.151463] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Hart PJ, O’Shaughnessy CM, Siggins MK, Bobat S, Kingsley RA, Goulding DA, Crump JA, Reyburn H, Micoli F, Dougan G, Cunningham AF, MacLennan CA. Differential Killing of Salmonella enterica Serovar Typhi by Antibodies Targeting Vi and Lipopolysaccharide O:9 Antigen. PLoS One 2016; 11:e0145945. [PMID: 26741681 PMCID: PMC4712142 DOI: 10.1371/journal.pone.0145945] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 12/10/2015] [Indexed: 01/08/2023] Open
Abstract
Salmonella enterica serovar Typhi expresses a capsule of Vi polysaccharide, while most Salmonella serovars, including S. Enteritidis and S. Typhimurium, do not. Both S. Typhi and S. Enteritidis express the lipopolysaccharide O:9 antigen, yet there is little evidence of cross-protection from anti-O:9 antibodies. Vaccines based on Vi polysaccharide have efficacy against typhoid fever, indicating that antibodies against Vi confer protection. Here we investigate the role of Vi capsule and antibodies against Vi and O:9 in antibody-dependent complement- and phagocyte-mediated killing of Salmonella. Using isogenic Vi-expressing and non-Vi-expressing derivatives of S. Typhi and S. Typhimurium, we show that S. Typhi is inherently more sensitive to serum and blood than S. Typhimurium. Vi expression confers increased resistance to both complement- and phagocyte-mediated modalities of antibody-dependent killing in human blood. The Vi capsule is associated with reduced C3 and C5b-9 deposition, and decreased overall antibody binding to S. Typhi. However, purified human anti-Vi antibodies in the presence of complement are able to kill Vi-expressing Salmonella, while killing by anti-O:9 antibodies is inversely related to Vi expression. Human serum depleted of antibodies to antigens other than Vi retains the ability to kill Vi-expressing bacteria. Our findings support a protective role for Vi capsule in preventing complement and phagocyte killing of Salmonella that can be overcome by specific anti-Vi antibodies, but only to a limited extent by anti-O:9 antibodies.
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Affiliation(s)
- Peter J. Hart
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Colette M. O’Shaughnessy
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Matthew K. Siggins
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Saeeda Bobat
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Robert A. Kingsley
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - David A. Goulding
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - John A. Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
- Kilimanjaro Christian Medical Centre and Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, United States of America
- Duke Global Health Institute, Duke University, Durham, United States of America
| | - Hugh Reyburn
- London School of Hygiene and Tropical Medicine, Keppel Street, London, United Kingdom
| | - Francesca Micoli
- Sclavo-Behring Vaccines Institute for Global Health, a GlaxoSmithKline Company, Siena, Italy
| | - Gordon Dougan
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | - Adam F. Cunningham
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Calman A. MacLennan
- School of Immunity and Infection, College of Medicine and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Abstract
Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed Salmonella Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: Salmonella Typhi, Salmonella Paratyphi A, Salmonella Paratyphi B (currently uncommon but may become dominant again), Salmonella Typhimurium, Salmonella Enteritidis and Salmonella Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines.
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Affiliation(s)
- Sharon M Tennant
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Myron M Levine
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA; Department of Pediatrics, University of Maryland School of Medicine, Baltimore, MD, USA.
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Abstract
Typhoid vaccination is an important component of typhoid fever prevention and control, and is recommended for public health programmatic use in both endemic and outbreak settings. We reviewed experiences with various vaccination strategies using the currently available typhoid vaccines (injectable Vi polysaccharide vaccine [ViPS], oral Ty21a vaccine, and injectable typhoid conjugate vaccine [TCV]). We assessed the rationale, acceptability, effectiveness, impact and implementation lessons of these strategies to inform effective typhoid vaccination strategies for the future. Vaccination strategies were categorized by vaccine disease control strategy (preemptive use for endemic disease or to prevent an outbreak, and reactive use for outbreak control) and vaccine delivery strategy (community-based routine, community-based campaign and school-based). Almost all public health typhoid vaccination programs used ViPS vaccine and have been in countries of Asia, with one example in the Pacific and one experience using the Ty21a vaccine in South America. All vaccination strategies were found to be acceptable, feasible and effective in the settings evaluated; evidence of impact, where available, was strongest in endemic settings and in the short- to medium-term. Vaccination was cost-effective in high-incidence but not low-incidence settings. Experience in disaster and outbreak settings remains limited. TCVs have recently become available and none are WHO-prequalified yet; no program experience with TCVs was found in published literature. Despite the demonstrated success of several typhoid vaccination strategies, typhoid vaccines remain underused. Implementation lessons should be applied to design optimal vaccination strategies using TCVs which have several anticipated advantages, such as potential for use in infant immunization programs and longer duration of protection, over the ViPS and Ty21a vaccines for typhoid prevention and control.
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Affiliation(s)
- Kashmira A Date
- Global Immunization Division, Centers for Disease Control and Prevention (CDC), Atlanta, GA 30329-4027, USA.
| | - Adwoa Bentsi-Enchill
- Department of Immunization, Vaccines and Biologicals (IVB), World Health Organization (WHO), Geneva, Switzerland
| | - Florian Marks
- International Vaccine Institute, Kwanak PO Box 14, Seoul 151-600, Republic of Korea
| | - Kimberley Fox
- World Health Organization Regional Office for the Western Pacific, United Nations Avenue, 1000 Manila, Philippines
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Peng ZH, Pan C, Sun P, Feng EL, Wu J, Zhu L, Peng QZ, Wang HL. Preparation and immunogenicity-evaluation of typhoid O-specific polysaccharides bio-conjugate vaccines. Yi Chuan 2015; 37:473-9. [PMID: 25998436 DOI: 10.16288/j.yczz.15-001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Typhoid fever caused by Salmonella Typhi is still a major public health problem in developing countries. In this study, we constructed a genetically modified Salmonella Typhi strain expressing O-specific polysaccharides (OPS) antigen conjugated to a carrier, recombinant Pseudomonas aeruginosa exotoxin A(rEPA N29). The conjugates (OPS-rEPA N29) were further purified and evaluated for their immunogenicity. The results of ELISA showed that the conjugates evoked higher titers of IgG than OPS, suggesting that rEPAN29 increased immunogenicity of OPS significantly as a carrier. Moreover, three injections with 3-week interval evoked slightly higher titers of IgG than three injections with 2-week interval. However, injection of excess conjugates could not evoke higher titers of IgG against lipid polysaccharide (LPS). In summary, our study provides a new strategy for preparing polysaccharides-protein conjugate vaccines as well as similar bio-conjugate vaccines of other Gram-negative pathogens.
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Affiliation(s)
- Zhe-hui Peng
- 1. College of Biology and Environmental Sciences, Jishou University, Jishou 416000, China; 2. State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Chao Pan
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Peng Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Er-ling Feng
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Jun Wu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Li Zhu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
| | - Qing-zhong Peng
- College of Biology and Environmental Sciences, Jishou University, Jishou 416000, China
| | - Heng-liang Wang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Biotechnology, Beijing 100071, China
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Qamar FN, Azmatullah A, Bhutta ZA. Challenges in measuring complications and death due to invasive Salmonella infections. Vaccine 2015; 33 Suppl 3:C16-20. [PMID: 25921727 DOI: 10.1016/j.vaccine.2015.03.103] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 03/26/2015] [Accepted: 03/28/2015] [Indexed: 01/08/2023]
Abstract
Despite the highest burden of Typhoid fever in children globally, exact estimates of morbidity and mortality are lacking due to scarcity of published data. Despite a high prevalence and a socioeconomic burden in developing countries, published data with morbidity and mortality figures are limited especially Africa and South American regions. Data from the community is insufficient and most case fatality estimates are extrapolations from hospital based studies that do not cover all geographical regions, and include cases which may or not be culture confirmed, MDR resistant or sensitive cases, or from mixed populations of age (adults and children). Complications of typhoid such as intestinal perforation, bone marrow suppression, and encephalopathy are dependent on MDR/Fluoroquinolone resistant Salmonella infection, comorbidities such as malnutrition, and health-care access. Data is again insufficient to estimate the true burden of Typhoid Fever in different regions and groups of populations. Although there has been a rapid decline in cases in developed countries with the advent of improved sanitization, timely and easy access to health care and laboratories, this is still not the case in the developing countries where Typhoid deaths are still occurring. The way forward is to develop rapid and cost effective point of care diagnostic tests, put in place validated clinical algorithms for suspected clinical cases, and design prospective, and community based studies in different groups, implement maintenance of electronic health records in large public sector hospitals and regions to identify populations that will benefit most from the implementation of vaccine. Policies on public health education and typhoid vaccine may help to reduce morbidity and mortality due to the disease.
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Affiliation(s)
- Farah Naz Qamar
- Department of Pediatrics and Child Health, Center of Excellence in Women and Child Health, The Aga Khan University, PO Box 3500, Karachi 74800, Pakistan.
| | - Asma Azmatullah
- Department of Pediatrics and Child Health, Center of Excellence in Women and Child Health, The Aga Khan University, PO Box 3500, Karachi 74800, Pakistan
| | - Zulfiqar A Bhutta
- Department of Pediatrics and Child Health, Center of Excellence in Women and Child Health, The Aga Khan University, PO Box 3500, Karachi 74800, Pakistan.
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Jackson BR, Iqbal S, Mahon B. Updated recommendations for the use of typhoid vaccine--Advisory Committee on Immunization Practices, United States, 2015. MMWR Morb Mortal Wkly Rep 2015; 64:305-8. [PMID: 25811680 PMCID: PMC4584884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
These revised recommendations of the Advisory Committee on Immunization Practices update recommendations published in MMWR in 1994 and include updated information on the two currently available vaccines and on vaccine safety. They also include an update on the epidemiology of enteric fever in the United States, focusing on increasing drug resistance in Salmonella enterica serotype Typhi, the cause of typhoid fever, as well as the emergence of Salmonella serotype Paratyphi A, a cause of paratyphoid fever, against which typhoid vaccines offer little or no protection.
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Affiliation(s)
- Brendan R. Jackson
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC
| | - Shahed Iqbal
- Division of Healthcare Quality Promotion, National Center for Emerging and Zoonotic Infectious Diseases, CDC
| | - Barbara Mahon
- Division of Foodborne, Waterborne, and Environmental Diseases, National Center for Emerging and Zoonotic Infectious Diseases, CDC
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Typhoid fever surveillance and vaccine use, South-East Asia and Western Pacific Regions, 2009–2013. Wkly Epidemiol Rec 2014; 89:429-39. [PMID: 25289402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Bhuiyan TR, Choudhury FK, Khanam F, Saha A, Sayeed MA, Salma U, Qadri F, Lundgren A, Svennerholm AM, Sack DA. Response on letter by Arya et al.: "evaluation of immune responses to an oral typhoid vaccine, Ty21a, in children from 2 to 5 years of age in Bangladesh.". Vaccine 2014; 32:4014. [PMID: 24837778 DOI: 10.1016/j.vaccine.2014.03.099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 03/26/2014] [Indexed: 11/19/2022]
Affiliation(s)
- Taufiqur R Bhuiyan
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Feroza K Choudhury
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Farhana Khanam
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Amit Saha
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Md Abu Sayeed
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Umme Salma
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh
| | - Firdausi Qadri
- Centre for Vaccine Sciences, International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b), Dhaka, Bangladesh.
| | - Anna Lundgren
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Ann-Mari Svennerholm
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - David A Sack
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
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Pitzer VE, Bowles CC, Baker S, Kang G, Balaji V, Farrar JJ, Grenfell BT. Predicting the impact of vaccination on the transmission dynamics of typhoid in South Asia: a mathematical modeling study. PLoS Negl Trop Dis 2014; 8:e2642. [PMID: 24416466 PMCID: PMC3886927 DOI: 10.1371/journal.pntd.0002642] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 11/27/2013] [Indexed: 12/02/2022] Open
Abstract
Background Modeling of the transmission dynamics of typhoid allows for an evaluation of the potential direct and indirect effects of vaccination; however, relevant typhoid models rooted in data have rarely been deployed. Methodology/Principal Findings We developed a parsimonious age-structured model describing the natural history and immunity to typhoid infection. The model was fit to data on culture-confirmed cases of typhoid fever presenting to Christian Medical College hospital in Vellore, India from 2000–2012. The model was then used to evaluate the potential impact of school-based vaccination strategies using live oral, Vi-polysaccharide, and Vi-conjugate vaccines. The model was able to reproduce the incidence and age distribution of typhoid cases in Vellore. The basic reproductive number (R0) of typhoid was estimated to be 2.8 in this setting. Vaccination was predicted to confer substantial indirect protection leading to a decrease in the incidence of typhoid in the short term, but (intuitively) typhoid incidence was predicted to rebound 5–15 years following a one-time campaign. Conclusions/Significance We found that model predictions for the overall and indirect effects of vaccination depend strongly on the role of chronic carriers in transmission. Carrier transmissibility was tentatively estimated to be low, consistent with recent studies, but was identified as a pivotal area for future research. It is unlikely that typhoid can be eliminated from endemic settings through vaccination alone. We developed a mathematical model for the transmission dynamics of typhoid in order to evaluate the potential direct and indirect (i.e. herd immunity) effects of vaccination. The model was fit to data from Vellore, India and validated against the results of cluster randomized vaccine trials. We evaluated a variety of school-based vaccination strategies and found that typhoid vaccination is expected to lead to short-term indirect protection and a decrease in typhoid incidence, but vaccination alone is unlikely to lead to elimination. The level of indirect protection was found to depend on assumptions about the role of chronic carriers, identifying an important area for future research.
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Affiliation(s)
- Virginia E. Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Cayley C. Bowles
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Stephen Baker
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom
- The London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gagandeep Kang
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India
| | - Veeraraghavan Balaji
- Department of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India
| | - Jeremy J. Farrar
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
- The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme, Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, Oxford, United Kingdom
| | - Bryan T. Grenfell
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America
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Bajracharya D, Khan MI, Pach A, Shrestha P, Joshi N, Upreti SR, Wierzba T, Puri M, Sahastrabuddhe S, Ochiai RL. 25 years after Vi typhoid vaccine efficacy study, typhoid affects significant number of population in Nepal. PLoS One 2014; 9:e77974. [PMID: 24400067 PMCID: PMC3882213 DOI: 10.1371/journal.pone.0077974] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 09/08/2013] [Indexed: 11/19/2022] Open
Abstract
Salmonella Typhi, first isolated in 1884, results in infection of the intestines and can end in death and disability. Due to serious adverse events post vaccination, whole cell killed vaccines have been replaced with new generation vaccines. The efficacy of Vi polysaccharide (ViPS) vaccine, a new generation, single-dose intramuscular typhoid vaccine was assessed in Nepal in 1987. However, despite the availability of ViPS vaccine for more than 25 years, Nepal has one of the highest incidence of typhoid fever. Therefore we collected information from hospitals in the Kathmandu Valley from over the past five years. There were 9901 enteric fever cases between January 2008 and July 2012. 1,881 of these were confirmed typhoid cases from five hospitals in the Kathmandu district. Approximately 70% of the cases involved children under 15 years old. 1281 cases were confirmed as S. Paratyphi. Vaccines should be prioritized for control of typhoid in conjunction with improved water and sanitation conditions in Nepal and in endemic countries of Asia and Africa.
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Affiliation(s)
- Deepak Bajracharya
- MITRA Samaj Pani Pokhari, Kathmandu, Nepal
- Group for Technical Assistance, Sanepa, Nepal
| | - M. Imran Khan
- International Vaccine Institute, Seoul, South Korea
- * E-mail:
| | - Alfred Pach
- International Vaccine Institute, Seoul, South Korea
| | | | | | - Shyam R. Upreti
- Child Health Division, Department of Health Services, Ministry of Health and Population, Kathmandu, Nepal
| | | | - Mahesh Puri
- International Vaccine Institute, Seoul, South Korea
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Abstract
BACKGROUND Typhoid fever and paratyphoid fever continue to be important causes of illness and death, particularly among children and adolescents in south-central and southeast Asia. Two typhoid vaccines are commercially available, Ty21a (oral) and Vi polysaccharide (parenteral), but neither is used routinely. Other vaccines, such as a new, modified, conjugated Vi vaccine called Vi-rEPA, are in development. OBJECTIVES To evaluate the efficacy and adverse effects of vaccines used to prevent typhoid fever. SEARCH METHODS In June 2013, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL, MEDLINE, EMBASE, LILACS, and mRCT. We also searched relevant conference proceedings up to 2013 and scanned the reference lists of all included trials. SELECTION CRITERIA Randomized and quasi-randomized controlled trials (RCTs) comparing typhoid fever vaccines with other typhoid fever vaccines or with an inactive agent (placebo or vaccine for a different disease). DATA COLLECTION AND ANALYSIS Two review authors independently applied inclusion criteria and extracted data. We computed vaccine efficacy per year of follow-up and cumulative three-year efficacy, stratifying for vaccine type and dose. The outcome addressed was typhoid fever, defined as isolation of Salmonella typhi in blood. We calculated risk ratios (RRs) and efficacy (1-RR as a percentage) with 95% confidence intervals (CIs). MAIN RESULTS In total, 18 RCTs were included in this review; 12 evaluated efficacy (Ty21a: five trials; Vi polysaccharide: six trials; Vi-rEPA: one trial), and 11 reported on adverse events. Ty21a vaccine (oral vaccine, three doses) A three-dose schedule of Ty21a vaccine prevents around one-third to one-half of typhoid cases in the first two years after vaccination (Year 1: 35%, 95% CI 8% to 54%; Year 2: 58%, 95% CI 40% to 71%; one trial, 20,543 participants; moderate quality evidence; data taken from a single trial conducted in Indonesia in the 1980s). No benefit was detected in the third year after vaccination. Four additional cluster-RCTs have been conducted, but the study authors did not adjust for clustering.Compared with placebo, this vaccine was not associated with more participants with vomiting, diarrhoea, nausea or abdominal pain (four trials, 2066 participants; moderate quality evidence) headache, or rash (two trials, 1190 participants; moderate quality evidence); however, fever (four trials, 2066 participants; moderate quality evidence) was more common in the vaccine group. Vi polysaccharide vaccine (injection, one dose) A single dose of Vi polysaccharide vaccine prevents around two-thirds of typhoid cases in the first year after vaccination (Year 1: 69%, 95% CI 63% to 74%; three trials, 99,979 participants; high quality evidence). In Year 2, the trial results were more variable, with the vaccine preventing between 45% and 69% of typhoid cases (Year 2: 59%, 95% CI 45% to 69%; four trials, 194,969 participants; moderate quality evidence). The three-year cumulative efficacy of the vaccine is around 55% (95% CI 30% to 70%; 11,384 participants, one trial; moderate quality evidence). These data are taken from a single trial in South Africa in the 1980s.Compared with placebo, this vaccine was not associated with more participants with fever (four trials, 133,038 participants; moderate quality evidence) or erythema (three trials, 132,261 participants; low quality evidence); however, swelling (three trials, 1767 participants; moderate quality evidence) and pain at the injection site (one trial, 667 participants; moderate quality evidence) were more common in the vaccine group. Vi-rEPA vaccine (two doses) Administration of two doses of the Vi-rEPA vaccine prevents between 50% and 96% of typhoid cases during the first two years after vaccination (Year 1: 94%, 95% CI 75% to 99%; Year 2: 87%, 95% CI 56% to 96%; one trial, 12,008 participants; moderate quality evidence). These data are taken from a single trial with children 2 to 5 years of age conducted in Vietnam.Compared with placebo, the first and second doses of this vaccine were not associated with increased risk of adverse events. The first dose of this vaccine was not associated with fever (2 studies, 12,209 participants; low quality evidence), erythema (two trials, 12,209 participants; moderate quality evidence) or swelling at the injection site (two trials, 12,209 participants; moderate quality evidence). The second dose of this vaccine was not associated with fever (two trials, 11,286 participants; low quality evidence), erythema (two trials, 11,286 participants; moderate quality evidence) and swelling at the injection site (two trials, 11,286 participants; moderate quality evidence). AUTHORS' CONCLUSIONS The licensed Ty21a and Vi polysaccharide vaccines are efficacious. The new and unlicensed Vi-rEPA vaccine is as efficacious and may confer longer immunity.
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Affiliation(s)
- Elspeth Anwar
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
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Bhutta ZA, Capeding MR, Bavdekar A, Marchetti E, Ariff S, Soofi SB, Anemona A, Habib MA, Alberto E, Juvekar S, Khan RMQ, Marhaba R, Ali N, Malubay N, Kawade A, Saul A, Martin LB, Podda A. Immunogenicity and safety of the Vi-CRM197 conjugate vaccine against typhoid fever in adults, children, and infants in south and southeast Asia: results from two randomised, observer-blind, age de-escalation, phase 2 trials. Lancet Infect Dis 2013; 14:119-29. [PMID: 24290843 DOI: 10.1016/s1473-3099(13)70241-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Typhoid vaccination is a public health priority in developing countries where young children are greatly affected by typhoid fever. Because present vaccines are not recommended for children younger than 2 years, the Novartis Vaccines Institute for Global Health developed a conjugate vaccine (Vi-CRM197) for infant immunisation. We aimed to assess the immunogenicity and safety of Vi-CRM197 in participants of various ages in endemic countries in south and southeast Asia. METHODS We did two randomised, observer-blind, age de-escalation, phase 2 trials at two sites in Pakistan and India (study A), and at one site in the Philippines (study B), between March 2, 2011, and Aug 9, 2012. Adults aged 18-45 years, children aged 24-59 months, older infants aged 9-12 months, and infants aged 6-8 weeks were randomly assigned (1:1) with a computer-generated randomisation list (block size of four) to receive either 5 μg Vi-CRM197 or 25 μg Vi-polysaccharide vaccine (or 13-valent pneumococcal conjugate vaccine in children younger than 2 years). Both infant populations received Vi-CRM197 concomitantly with vaccines of the Expanded Programme on Immunization (EPI), according to WHO schedule. With the exception of designated study site personnel responsible for vaccine preparation, study investigators, those assessing outcomes, and data analysts were masked to treatment allocation. We specified no a-priori null hypothesis for the immunogenicity or safety objectives and all analyses were descriptive. Analyses were by modified intention-to-treat. These studies are registered with ClinicalTrials.gov, numbers NCT01229176 and NCT01437267. FINDINGS 320 participants were enrolled and vaccinated in the two trials: 200 in study A (all age groups) and 120 in study B (children and infants only), of whom 317 (99%) were included in the modified intention-to-treat analysis. One dose of Vi-CRM197 significantly increased concentrations of anti-Vi antibody in adults (from 113 U/mL [95% CI 67-190] to 208 U/mL [117-369]), children (201 U/mL [138-294] to 368 U/mL [234-580]), and older infants (179 U/mL [129-250] to 249 U/mL [130-477]). However, in children and older infants, a second dose of conjugate vaccine had no incremental effect on antibody titres and, at all ages, concentrations of antibodies increased substantially 6 months after vaccination (from 55 U/mL [33-94] to 63 U/mL [35-114] in adults, from 23 U/mL [15-34] to 51 U/mL [34-76] in children, and from 21 U/mL [14-31] to 22 U/mL [14-33] in older infants). Immune response in infants aged 6-8 weeks was lower than that in older participants and, 6 months after third vaccination, antibody concentrations were significantly higher than pre-vaccination concentrations in Filipino (21 U/mL [16-28] vs 2.88 U/mL [1.95-4.25]), but not Pakistani (3.76 U/mL [2.77-5.08] vs 2.77 U/mL [2.1-3.66]), infants. Vi-CRM197 was safe and well tolerated and did not induce any significant interference with EPI vaccines. No deaths or vaccine-related serious adverse events were reported throughout the studies. INTERPRETATION Vi-CRM197 is safe and immunogenic in endemic populations of all ages. Given at 9 months of age, concomitantly with measles vaccine, Vi-CRM197 shows a promise for potential inclusion in EPI schedules of countries endemic for typhoid. An apparent absence of booster response and a reduction in antibody titres 6 months after immunisation should be further investigated, but data show that an immunogenic typhoid vaccine can be safely delivered to infants during EPI visits recommended by WHO. FUNDING Sclavo Vaccines Association and Regione Toscana.
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Affiliation(s)
- Zulfiqar A Bhutta
- Department of Pediatrics and Child Health, Division of Women and Child Health, Aga Khan University, Karachi, Pakistan
| | | | - Ashish Bavdekar
- King Edward Memorial Hospital Research Centre, Rasta Peth, Pune, India
| | | | - Shabina Ariff
- Novartis Vaccines Institute for Global Health, Siena, Italy
| | - Sajid B Soofi
- Department of Pediatrics and Child Health, Division of Women and Child Health, Aga Khan University, Karachi, Pakistan
| | | | - Muhammad A Habib
- Department of Pediatrics and Child Health, Division of Women and Child Health, Aga Khan University, Karachi, Pakistan
| | - Edison Alberto
- Research Institute for Tropical Medicine, Manila, Philippines
| | - Sanjay Juvekar
- King Edward Memorial Hospital Research Centre, Rasta Peth, Pune, India
| | | | - Rachid Marhaba
- Novartis Vaccines and Diagnostics Human Serology Laboratories, Marburg, Germany
| | - Noshad Ali
- Department of Pediatrics and Child Health, Division of Women and Child Health, Aga Khan University, Karachi, Pakistan
| | - Nelia Malubay
- Research Institute for Tropical Medicine, Manila, Philippines
| | - Anand Kawade
- King Edward Memorial Hospital Research Centre, Rasta Peth, Pune, India
| | - Allan Saul
- Novartis Vaccines Institute for Global Health, Siena, Italy
| | - Laura B Martin
- Novartis Vaccines Institute for Global Health, Siena, Italy
| | - Audino Podda
- Novartis Vaccines Institute for Global Health, Siena, Italy.
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