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Batool R, Yousafzai MT, Mir F, Muhammad S, Shaikh SA, Memon S, Qamar FN. Longevity of serologic responses following a single dose of typhoid conjugate vaccine among children living with HIV in Pakistan: A prospective cohort study. Vaccine 2024:S0264-410X(24)00625-X. [PMID: 38811267 DOI: 10.1016/j.vaccine.2024.05.057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 05/31/2024]
Abstract
BACKGROUND This study aimed to assess the longevity of serologic response and seroconversion rates at several time points following TCV vaccination among children living with HIV aged 6 months to 15 years in Pakistan. METHODS From November 20, 2020, to January 2, 2021; 336 children were enrolled and followed up prospectively for 12 months. Blood samples were collected before the administration of TCV and at 4-6 weeks, 6 months, and 1 year after administration of a single dose (0.5 ml) of intramuscular Typbar TCV®. Samples were analyzed for anti-Vi-IgG antibodies using ELISA. Geometric mean titers (GMTs), seroconversion rates (fourfold rise in anti-Vi-IgG from baseline), and factors associated with sustained seroconversion at 1 year were evaluated using generalized linear mixed models. FINDINGS The seroconversion rates were significantly lower in children aged 6 months to 5 years compared to children > 5 years; (127/216 (58·8%)) versus (81/111 (73·0%)) at 6 months and (110/217 (50·7%)) versus (78/109 (71·6%)) at 1 year, only two-third; 188/326 (57·7%) remained seroconverted at 1 year. The GMTs (95 % CI) were significantly lower in children aged 6 months to 5 years compared to children > 5 years, 9·6 (7·6, 12·0) versus 28·9 (20·2, 41·4) at 6 months, and 6·6 (5·4, 8·0) versus 23·1 (16·4, 32·5) at 1 year time point. The odds of sustained seroconversion significantly decreased with time (adjusted odds ratio (aOR): 0·232; 95 % CI: 0·136,0·396). The odds of sustained seroconversion following 1 year of TCV vaccination were significantly higher among children with non-severe HIV clinical disease (aOR: 10·6; 95 % CI: 1·5, 73·9) and children in elder age group (aOR: 7·45; 95 % CI: 11·2, 47·0). CONCLUSIONS There was a decline in seroconversion after one year of TCV in children living with HIV. The decline was significant in children with severe or advanced HIV disease. A significant decrease in seroconversion rates was observed among children living with HIV following one year of TCV administration.
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Affiliation(s)
- Rabab Batool
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500, Karachi 74800, Pakistan; Centre for Child, Adolescent, and Maternal Health Research, Faculty of Medicine and Health Technology, Tampere University, Arvo Ylpön katu 34, Tampere 33520, Finland
| | - Mohammad Tahir Yousafzai
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500, Karachi 74800, Pakistan
| | - Fatima Mir
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500, Karachi 74800, Pakistan
| | - Sajid Muhammad
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500, Karachi 74800, Pakistan
| | - Saqib Ali Shaikh
- Director Health Services Karachi, Division, Civic Centre, 06th Floor, Hassan Square, Karachi, Karachi, Pakistan
| | - Sikander Memon
- New Secretariat Building, 6th Floor, Sindh Kamal Atta Turk Road, Shahrah-e-Kemal Ataturk, Burns Road, Karachi, Pakistan
| | - Farah Naz Qamar
- Department of Paediatrics and Child Health, Aga Khan University Hospital, Stadium Rd, PO Box 3500, Karachi 74800, Pakistan.
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Patel PD, Liang Y, Meiring JE, Chasweka N, Patel P, Misiri T, Mwakiseghile F, Wachepa R, Banda HC, Shumba F, Kawalazira G, Dube Q, Nampota-Nkomba N, Nyirenda OM, Girmay T, Datta S, Jamka LP, Tracy JK, Laurens MB, Heyderman RS, Neuzil KM, Gordon MA. Efficacy of typhoid conjugate vaccine: final analysis of a 4-year, phase 3, randomised controlled trial in Malawian children. Lancet 2024; 403:459-468. [PMID: 38281499 PMCID: PMC10850983 DOI: 10.1016/s0140-6736(23)02031-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/18/2023] [Accepted: 09/18/2023] [Indexed: 01/30/2024]
Abstract
BACKGROUND Randomised controlled trials of typhoid conjugate vaccines among children in Africa and Asia have shown high short-term efficacy. Data on the durability of protection beyond 2 years are sparse. We present the final analysis of a randomised controlled trial in Malawi, encompassing more than 4 years of follow-up, with the aim of investigating vaccine efficacy over time and by age group. METHODS In this phase 3, double-blind, randomised controlled efficacy trial in Blantyre, Malawi, healthy children aged 9 months to 12 years were randomly assigned (1:1) by an unmasked statistician to receive a single dose of Vi polysaccharide conjugated to tetanus toxoid vaccine (Vi-TT) or meningococcal capsular group A conjugate (MenA) vaccine. Children had to have no previous history of typhoid vaccination and reside in the study areas for inclusion and were recruited from government schools and health centres. Participants, their parents or guardians, and the study team were masked to vaccine allocation. Nurses administering vaccines were unmasked. We did surveillance for febrile illness from vaccination until follow-up completion. The primary outcome was first occurrence of blood culture-confirmed typhoid fever. Eligible children who were randomly assigned and vaccinated were included in the intention-to-treat analyses. This trial is registered at ClinicalTrials.gov, NCT03299426. FINDINGS Between Feb 21, 2018, and Sept 27, 2018, 28 130 children were vaccinated; 14 069 were assigned to receive Vi-TT and 14 061 to receive MenA. After a median follow-up of 4·3 years (IQR 4·2-4·5), 24 (39·7 cases per 100 000 person-years) children in the Vi-TT group and 110 (182·7 cases per 100 000 person-years) children in the MenA group were diagnosed with a first episode of blood culture-confirmed typhoid fever. In the intention-to-treat population, efficacy of Vi-TT was 78·3% (95% CI 66·3-86·1), and 163 (129-222) children needed to be vaccinated to prevent one case. Efficacies by age group were 70·6% (6·4-93·0) for children aged 9 months to 2 years; 79·6% (45·8-93·9) for children aged 2-4 years; and 79·3% (63·5-89·0) for children aged 5-12 years. INTERPRETATION A single dose of Vi-TT is durably efficacious for at least 4 years among children aged 9 months to 12 years and shows efficacy in all age groups, including children younger than 2 years. These results support current WHO recommendations in typhoid-endemic areas for mass campaigns among children aged 9 months to 15 years, followed by routine introduction in the first 2 years of life. FUNDING Bill & Melinda Gates Foundation.
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Affiliation(s)
- Priyanka D Patel
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Yuanyuan Liang
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - James E Meiring
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Nedson Chasweka
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Pratiksha Patel
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Theresa Misiri
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Felistas Mwakiseghile
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Richard Wachepa
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Happy C Banda
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Florence Shumba
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Gift Kawalazira
- District Health Office, Blantyre District Council, Blantyre, Malawi
| | | | | | - Osward M Nyirenda
- Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Tsion Girmay
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shrimati Datta
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Leslie P Jamka
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - J Kathleen Tracy
- Department of Epidemiology and Public Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Matthew B Laurens
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Robert S Heyderman
- Division of Infection and Immunity, University College London, London, UK
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Program, Kamuzu University of Health Sciences, Blantyre, Malawi
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Meiring JE, Khanam F, Basnyat B, Charles RC, Crump JA, Debellut F, Holt KE, Kariuki S, Mugisha E, Neuzil KM, Parry CM, Pitzer VE, Pollard AJ, Qadri F, Gordon MA. Typhoid fever. Nat Rev Dis Primers 2023; 9:71. [PMID: 38097589 DOI: 10.1038/s41572-023-00480-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/06/2023] [Indexed: 12/18/2023]
Abstract
Typhoid fever is an invasive bacterial disease associated with bloodstream infection that causes a high burden of disease in Africa and Asia. Typhoid primarily affects individuals ranging from infants through to young adults. The causative organism, Salmonella enterica subsp. enterica serovar Typhi is transmitted via the faecal-oral route, crossing the intestinal epithelium and disseminating to systemic and intracellular sites, causing an undifferentiated febrile illness. Blood culture remains the practical reference standard for diagnosis of typhoid fever, where culture testing is available, but novel diagnostic modalities are an important priority under investigation. Since 2017, remarkable progress has been made in defining the global burden of both typhoid fever and antimicrobial resistance; in understanding disease pathogenesis and immunological protection through the use of controlled human infection; and in advancing effective vaccination programmes through strategic multipartner collaboration and targeted clinical trials in multiple high-incidence priority settings. This Primer thus offers a timely update of progress and perspective on future priorities for the global scientific community.
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Affiliation(s)
- James E Meiring
- Division of Clinical Medicine, School of Medicine and Population Health, University of Sheffield, Sheffield, UK
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi
| | - Farhana Khanam
- International Centre for Diarrhoel Disease Research, Dhaka, Bangladesh
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Kathmandu, Nepal
| | - Richelle C Charles
- Massachusetts General Hospital, Harvard Medical School, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - John A Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
| | | | - Kathryn E Holt
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK
- Department of Infectious Diseases, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Samuel Kariuki
- Centre for Microbiology Research, Kenya Medical Research Institute, Nairobi, Kenya
| | - Emmanuel Mugisha
- Center for Vaccine Innovation and Access, PATH, Seattle, WA, USA
| | - Kathleen M Neuzil
- Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christopher M Parry
- Department of Clinical Sciences and Education, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases and Public Health Modelling Unit, Yale School of Public Health, Yale University, New Haven, CT, USA
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, Oxford, UK
- NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Firdausi Qadri
- International Centre for Diarrhoel Disease Research, Dhaka, Bangladesh
| | - Melita A Gordon
- Malawi-Liverpool-Wellcome Programme, Blantyre, Malawi.
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK.
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