TyVOID

Typhoid vaccines that work well for two years may begin to fail in children who need protection the longest, and this project will find out whether booster shots are necessary. The problem is straightforward: typhoid fever still sickens and kills children and young people in parts of South Asia and Africa, even though an effective vaccine exists. The World Health Organization approved a typhoid conjugate vaccine years ago, but no one knows whether a single dose protects for more than two years. If immunity fades, children remain vulnerable, and vaccination programmes may waste resources on a strategy that leaves them unprotected later. This research will track antibody levels in vaccinated children over several years, compare those immune responses to actual typhoid cases in the community, and build mathematical models that predict what happens if booster doses are added to the schedule. If the results show that protection wanes, governments and global health agencies will have the evidence they need to recommend booster shots, potentially preventing thousands of cases and deaths. If protection holds, they can avoid unnecessary extra doses and keep vaccination campaigns simple and cheap. Either way, the work directly answers a question the WHO’s vaccine advisory group posed in 2017, and the findings will shape how typhoid is controlled in the places where it remains a threat.