Protection by vaccination of children against typhoid fever with a Vi-tetanus toxoid conjugate vaccine in urban Bangladesh: a cluster-randomised trial.

Autor:	Qadri F; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh. Electronic address: fqadri@icddrb.org., Khanam F; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Liu X; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Theiss-Nyland K; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Biswas PK; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Bhuiyan AI; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Ahmmed F; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Colin-Jones R; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Smith N; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Tonks S; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Voysey M; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Mujadidi YF; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Mazur O; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Rajib NH; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Hossen MI; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Ahmed SU; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Khan A; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Rahman N; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Babu G; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Greenland M; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Kelly S; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Ireen M; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Islam K; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., O'Reilly P; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Scherrer KS; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Pitzer VE; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT USA., Neuzil KM; University of Maryland School of Medicine, Baltimore MD, USA., Zaman K; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh., Pollard AJ; Oxford Vaccine Group, Department of Paediatrics, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, UK., Clemens JD; International Centre for Diarrhoeal Disease Research, Bangladesh, Dhaka, Bangladesh; University of California Los Angeles, Fielding School of Public Health, Los Angeles, CA, USA.
Jazyk:	angličtina
Zdroj:	Lancet (London, England) [Lancet] 2021 Aug 21; Vol. 398 (10301), pp. 675-684. Date of Electronic Publication: 2021 Aug 09.
DOI:	10.1016/S0140-6736(21)01124-7
Abstrakt:	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. Competing Interests: Declaration of interests VEP has received reimbursement from Merck and Pfizer for travel expenses to scientific input engagements unrelated to the topic of this manuscript and is a member of the WHO Immunization and Vaccine-related Implementation Research Advisory Committee. All other authors declare no competing interests. (Copyright © 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)
Databáze:	MEDLINE
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