A single dose of the typhoid conjugate vaccine Typbar TCV provides lasting efficacy in preventing typhoid fever in children aged nine months to 12 years old, according to a new study.
Results from the phase three clinical study, conducted by researchers at the University of Maryland School of Medicine and led by in-country partners at the Malawi-Liverpool Wellcome Trust Clinical Research Programme, have been published in The Lancet.
The research team enrolled more than 28,000 healthy children in Malawi and randomly assigned about half the group to receive the TCV and the other half to receive a meningococcal capsular group A conjugate (MenA) control vaccine.
During the more than four years of follow-up, 24 children in the TCV group and 110 in the MenA group developed typhoid fever.
That resulted in an efficacy of 78.3% in the TCV group, with one case of typhoid prevented for every 163 children vaccinated.
TCV was effective in all age groups. Over the study period, which ended in 2022, vaccine efficacy only decreased by 1.3% per year.
Typhoid fever causes more than nine million illnesses and at least 110,000 deaths worldwide every year, mostly in sub-Saharan Africa and southeast Asia.
It is a contagious bacterial infection that occurs from consuming contaminated food or drink. Symptoms include nausea, fever, and abdominal pain that, if left untreated, can be deadly.
“These findings have significant implications for identification of the contribution of TCVs in the control and potential elimination of typhoid fever in endemic settings,” wrote the authors of a commentary published with the study.
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