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Huoi C, Vargas-Zambrano J, Macina D, Vidor E. A combined DTaP-IPV vaccine (Tetraxim®/Tetravac®) used as school-entry booster: a review of more than 20 years of clinical and post-marketing experience. Expert Rev Vaccines 2022; 21:1215-1231. [PMID: 35983656 DOI: 10.1080/14760584.2022.2084076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Routine infant primary series and toddler booster vaccination are associated with waning of antibody levels over time, which can lead to an increased incidence of vaccine-preventable diseases. A diphtheria-tetanus-pertussis (DTP) booster vaccination at school-entry (aged 4-7 years) allows continued protection against these diseases and is included in many national immunization programs. AREAS COVERED The available immunogenicity and safety data from 6 clinical studies of a diphtheria-tetanus-acellular pertussis-inactivated poliovirus vaccine (DTaP-IPV [Tetraxim®]) used as a school-entry booster vaccination were identified using a PubMed search or on file at Sanofi. The studies spanned a 15-year period (1995-2010) and were performed in different populations using different study designs, so all data were reviewed descriptively (no meta-analyses were conducted). Additionally, post-marketing experience was reviewed. EXPERT OPINION Each vaccine antigen is highly immunogenic, and the safety profile of the vaccine is satisfactory. Post-marketing evaluations have shown the effectiveness of a school-age booster, particularly against increased pertussis disease incidence around the time of school entry and the associated risk of spreading the disease through contact with younger vulnerable infants. School-entry provides an ideal opportunity to implement DTaP-IPV vaccination to close the gap between waning immunity from the previous infant/toddler vaccination and future adolescent vaccination.
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Liu X, Pitzer VE, Pollard AJ, Voysey M. The Design and Analysis of Seroefficacy Studies for Typhoid Conjugate Vaccines. Clin Infect Dis 2020; 68:S183-S190. [PMID: 30845326 PMCID: PMC6405265 DOI: 10.1093/cid/ciy1119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Background Demonstrating the efficacy of new Vi-conjugate typhoid vaccines is challenging, due to the cost of field trials requiring tens of thousands of participants. New trial designs that use serologically defined typhoid infections (seroefficacy trials) rather than blood culture positivity as a study endpoint may be useful to assess efficacy using small trials. Methods We developed a model for Vi–immunoglobin G antibody responses to a Vi-vaccine, incorporating decay over time and natural boosting due to endemic exposures. From this, we simulated clinical trials in which 2 blood samples were taken during follow-up and the relative risk of a serologically defined typhoid infection (seroefficacy) was computed. We aimed to determine (1) whether seroefficacy trial designs could substantially reduce sample sizes, compared with trials using blood culture–confirmed cases; (3) whether the rate of case detection was higher in seroefficacy trials; and (3) the optimal timing of sample collection. Results The majority (>90%) of blood culture–positive typhoid cases remain unobserved in surveillance studies. In contrast, under-detection in simulated seroefficacy trials of equivalent vaccines was as little as 26%, and estimates of the relative risk of typhoid infection were unbiased. For simulated trials of non-equivalent vaccines, relative risks were slightly inflated by at least 5%, depending on the sample collection times. Seroefficacy trials required as few as 460 participants per arm, compared with 10 000 per arm for trials using blood culture–confirmed cases. Conclusions Seroefficacy trials can establish the efficacy of new conjugate vaccines using small trials that enroll hundreds rather than thousands of participants, and without the need for resource-intensive typhoid fever surveillance programs.
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Affiliation(s)
- Xinxue Liu
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Merryn Voysey
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
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Desai S, Scobie HM, Cherian T, Goodman T. Use of tetanus-diphtheria (Td) vaccine in children 4-7 years of age: World Health Organization consultation of experts. Vaccine 2020; 38:3800-3807. [PMID: 31983584 PMCID: PMC7286697 DOI: 10.1016/j.vaccine.2020.01.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 01/07/2020] [Indexed: 12/04/2022]
Abstract
For lifetime protection against diphtheria and tetanus, the World Health Organization (WHO) recommends six doses of diphtheria and tetanus containing vaccines. Td (reduced diphtheria toxoid, ≥2-5 IU) vaccines are currently licensed for ages 7 years and older, but use of Td vaccine for ages 4 years and older would have advantages for immunization programs in many low- and middle-income countries. For this reason, WHO convened an expert consultation to review the currently available evidence for the use of Td vaccine from 4 to 7 years of age which concluded: (1) no relevant biological difference in immune response in the relevant age group compared with children over 7 years of age; (2) adequate seroprotection in several studies with Td vaccine in the 4-7 age group and many studies using combination vaccines; (3) durable and protective response of at least 9-11 years duration in several longitudinal and modelling studies, (4) less reactogenicity compared with use of full-dose diphtheria vaccine, potentially improving the vaccination experience; and (5) adequate control of diphtheria in several countries using Td-containing combination vaccines in 4-7 year old children. On this basis, the experts concluded that from a programmatic perspective, Td vaccine given in ages 4-7 years, as a second booster dose in a six-dose series, would provide adequate protection against diphtheria and tetanus and recommended steps to include this change in age extension listed in the package insert.
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Affiliation(s)
- Shalini Desai
- World Health Organization, 20 Appia Avenue, Geneva, Switzerland.
| | - Heather M Scobie
- Global Immunization Division, Centers for Disease Control and Prevention, 1600 Clifton Rd, Atlanta GA, USA.
| | - Thomas Cherian
- MMGH Consulting GmbH, Kuerbergstrasse 1, 8049 Zurich, Switzerland.
| | - Tracey Goodman
- World Health Organization, 20 Appia Avenue, Geneva, Switzerland.
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Voysey M, Pollard AJ. Seroefficacy of Vi Polysaccharide-Tetanus Toxoid Typhoid Conjugate Vaccine (Typbar TCV). Clin Infect Dis 2019; 67:18-24. [PMID: 29351594 DOI: 10.1093/cid/cix1145] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/04/2018] [Indexed: 11/14/2022] Open
Abstract
Background Salmonella Typhi is the major cause of enteric fever in lower-income countries. New conjugate vaccines show promise as public health interventions, but there are no efficacy data available from endemic areas. Methods Data were obtained from a previously published phase 3 randomized controlled trial comparing Vi polysaccharide-tetanus toxoid conjugate vaccine (Vi-TT) with Vi polysaccharide vaccine (Vi-PS) in participants aged 2-45 years. An additional open-label arm administered Vi-TT to children aged 6-23 months. The proportion of participants with presumed clinical or subclinical infection ("seroincidence") was determined using mixture models and compared using relative risks (RRs). Results Of 387 participants, 81 (21%) were classified as having presumed typhoid infection during the 2-year postvaccination period. Seroincidence was lower in participants randomized to Vi-TT rather than Vi-PS among those aged 2-45 years (RR, 0.372; 95% confidence interval [CI], .235-.588; P < .001) and those aged 2-15 years (RR, 0.424; 95% CI, .231-.778; P = .004). There was no difference in seroincidence for Vi-TT between those aged 2-45 years and those aged 6-23 months (RR, 1.073; 95% CI, .563-2.046; P = .83). Vaccine seroefficacy was 85% (95% CI, 80%-88%). Conclusion This is the first field estimate of the seroefficacy of a Vi-TT vaccine and shows that Typbar TCV substantially reduces the number of serologically defined clinical or subclinical infections in infants, children, and adults. These results support the recent World Health Organization recommendations for deployment of typhoid conjugate vaccines in high-burden areas.
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Affiliation(s)
- Merryn Voysey
- Nuffield Department of Primary Care Health Sciences, University of Oxford, United Kingdom.,Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, United Kingdom.,NIHR Oxford Biomedical Research Centre, United Kingdom
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Pitisuttithum P, Chokephaibulkit K, Sirivichayakul C, Sricharoenchai S, Dhitavat J, Pitisuthitham A, Phongsamart W, Boonnak K, Lapphra K, Sabmee Y, Wittawatmongkol O, Chauhan M, Wijagkanalan W, Hommalai G, Fortuna L, Chinwangso P, Poredi IK, van den Biggelaar AHJ, Pham HT, Viviani S. Antibody persistence after vaccination of adolescents with monovalent and combined acellular pertussis vaccines containing genetically inactivated pertussis toxin: a phase 2/3 randomised, controlled, non-inferiority trial. THE LANCET. INFECTIOUS DISEASES 2018; 18:1260-1268. [PMID: 30266329 DOI: 10.1016/s1473-3099(18)30375-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 06/04/2018] [Accepted: 06/05/2018] [Indexed: 10/28/2022]
Abstract
BACKGROUND The immunogenicity of acellular pertussis vaccines and persistence of immunity after vaccination might be improved by using genetically inactivated pertussis toxin (PTgen) instead of chemically inactivated pertussis toxin (PTchem) because of the preservation of conformational epitopes. We assessed the safety and immunogenicity of two vaccines containing PTgen 1 year after vaccination. METHODS We did a phase 2/3 non-inferiority, randomised, controlled trial involving 450 adolescents (age 12-17 years) enrolled between July 6, 2015, and Aug 20, 2015. Participants were randomised 1:1:1 to receive one dose of vaccine containing PTgen and filamentous haemagglutinin (FHA) either in a monovalent formulation (aP[PTgen/FHA]) or in a combined formulation with tetanus and reduced-dose diphtheria toxoids (TdaP[PTgen/FHA]) or to receive a commercial vaccine containing reduced-dose PTchem (Tdap) as a comparator. We report a secondary trial outcome, namely antibody persistence 1 year after vaccination, assessed per protocol in 150 randomly preselected participants (50 per group). Seroconversion was defined as antibody titres at least four times greater than at baseline. Safety was assessed in all trial participants. This study is registered in the Thai Clinical Trial Registry, number TCTR20150703002. FINDINGS Between June 5, 2016, and Aug 9, 2016, 442 (98%) of 450 enrolled participants attended a 1-year follow-up visit. After 1 year, persistent seroconversion for pertussis toxin neutralising antibodies was seen in 38 (76%, 95% CI 64-88) participants in the aP(PTgen/FHA) group and 41 (81%, 70-92) in the TdaP(PTgen/FHA) group, but in only four (8%, 1-16) in the Tdap comparator group. Seroconversion rates for IgG antibodies against pertussis toxin and FHA were also greater in the aP(PTgen/FHA) group (82%, 95% CI 71-93 and 64%, 51-77, respectively) and TdaP(PTgen/FHA) group (75%, 63-87 and 56%, 42-70, respectively) than in the Tdap group (4%, 0-9, p<0·0001, and 28%, 16-41, p=0·0007, respectively). 13 serious adverse events were reported in 12 participants and all were judged to be unrelated to the study vaccines. Five pregnancies were reported during follow-up, none of which had any maternal or neonatal complications. INTERPRETATION A monovalent and a combined recombinant acellular pertussis vaccine containing PTgen induced antibody responses that were greater and sustained for longer than those achieved with the Tdap comparator vaccine. New recombinant pertussis vaccines containing PTgen might offer new opportunities to limit pertussis resurgence and can be widely used, including in pregnant women. FUNDING BioNet-Asia.
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Affiliation(s)
- Punnee Pitisuttithum
- Vaccine Trial Centre, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Kulkanya Chokephaibulkit
- Paediatric Infectious Diseases Unit, Department of Paediatrics, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand
| | - Chukiat Sirivichayakul
- Department of Tropical Paediatrics, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Sirintip Sricharoenchai
- Paediatric Infectious Diseases Unit, Department of Paediatrics, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand
| | - Jittima Dhitavat
- Vaccine Trial Centre, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Arom Pitisuthitham
- Vaccine Trial Centre, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Wanatpreeya Phongsamart
- Paediatric Infectious Diseases Unit, Department of Paediatrics, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand
| | - Kobporn Boonnak
- Vaccine Trial Centre, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Keswadee Lapphra
- Paediatric Infectious Diseases Unit, Department of Paediatrics, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand
| | - Yupa Sabmee
- Vaccine Trial Centre, Faculty of Tropical Medicine, Mahidol University, Ratchathewi, Bangkok, Thailand
| | - Orasri Wittawatmongkol
- Paediatric Infectious Diseases Unit, Department of Paediatrics, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand
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Voysey M, Pollard AJ, Sadarangani M, Fanshawe TR. Prevalence and decay of maternal pneumococcal and meningococcal antibodies: A meta-analysis of type-specific decay rates. Vaccine 2017; 35:5850-5857. [PMID: 28935471 PMCID: PMC5628610 DOI: 10.1016/j.vaccine.2017.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 08/23/2017] [Accepted: 09/03/2017] [Indexed: 11/30/2022]
Abstract
Background At the time of an infant’s initial vaccination at age ∼2 to 3 months, some infants already have maternal antibodies against vaccine antigens and these can suppress the immune response to vaccination. Modelling the effects of maternal antibody and the timing of infant doses on the antibody response to vaccination, requires estimates of the rate of maternal antibody decay. Decay rates are not well characterised in the medical literature. We investigated variation in the prevalence of maternal anti-capsular pneumococcal and meningococcal antibodies in infants in 14 countries, and estimated type-specific half-lives. Methods Individual participant serological data were obtained from clinical trials. Half-lives were estimated from antibody concentrations in infants who did not receive meningococcal or pneumococcal vaccines. Results The seroprevalence of maternal pneumococcal antibodies was highest for serotypes 14, and 19F (92% and 80% respectively) and lowest for serotypes 4 and 1 (30% and 34% respectively). Half-life estimates ranged from 38.7 days (95% CI 36.6–41.0) for serotype 6B, to 48.3 days (95% CI 46.7–50.2) for serotype 5. The overall half-life was 42.6 days (95% CI 41.5–43.7). Seroprevalence was highest in Mali, Nigeria, India, and the Philippines, (all >65%) and lowest in the Czech Republic and Finland (both <45%). In studies of meningococcal vaccines, seroprevalence was 13% for group C (half-life 39.8 days, 95% CI 33.4–49.4) and 43% for group A (half-life 43.1 days 95% CI 39.8–47.2). Conclusion Substantial proportions of infants in many countries have antibodies to vaccine serotypes of pneumococcus, however fewer infants have maternally acquired antibodies to groups A and C meningococcus. Passively-acquired antibodies to capsular polysaccharides decay with a half-life of approximately 6 weeks. These estimates are useful for modelling the impact of proposed vaccination programmes, and consideration of schedules with a delayed start.
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Affiliation(s)
- Merryn Voysey
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, UK.
| | - Andrew J Pollard
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, UK
| | - Manish Sadarangani
- Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and NIHR Oxford Biomedical Research Centre, Oxford, UK; Vaccine Evaluation Center, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Thomas R Fanshawe
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
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Chen Z, He Q. Immune persistence after pertussis vaccination. Hum Vaccin Immunother 2017; 13:744-756. [PMID: 28045580 PMCID: PMC5404361 DOI: 10.1080/21645515.2016.1259780] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 10/20/2016] [Accepted: 11/08/2016] [Indexed: 12/17/2022] Open
Abstract
Pertussis is one of the most prevalent vaccine-preventable diseases worldwide. The true infection rate is significantly higher than the reported incidence rate. An increased prevalence of pertussis in older populations has been found, mainly caused by waning immunity after vaccination. Vaccine-induced immunity differs due to variation in vaccine content, schedule and coverage. Protection following acellular pertussis vaccines has been suggested to wane faster than whole cell pertussis vaccines. However, long-term immune persistence of whole cell pertussis vaccines may be confounded by a progressive acquisition of natural immunity. The World Health Organization has recommended that a switch from whole cell to acellular pertussis vaccines for primary immunization in infants should only be considered if additional periodic boosters or maternal immunization can be ensured and sustained in the national immunization schedules. In this review, we present data on immune persistence after different pertussis vaccinations and compare the findings from countries with different vaccination strategies. Future aspects in serological studies are briefly discussed.
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Affiliation(s)
- Zhiyun Chen
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing, China
| | - Qiushui He
- Department of Medical Microbiology and Research Centre of Microbiome, Capital Medical University, Beijing, China
- Department of Medical Microbiology and Immunology, University of Turku, Turku, Finland
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