One-shot typhoid vaccine provides long-term protection for kids

The vaccine, called Typbar TCV, requires just one dose and shielded children ages 9 months to 12 years over the course of a four-year study, researchers reported. Photo by Adobe Stock/HealthDay News

While largely eliminated in more affluent nations, typhoid remains a deadly scourge in developing countries, killing more than 110,000 children every year.

Children in endemic areas — mainly sub-Saharan Africa and southeast Asia — have new reason to hope, however, with the advent of a one-shot vaccine that appears to provide long-term protection against the typhoid bacterium.

The vaccine, called Typbar TCV, requires just one dose and shielded children ages 9 months to 12 years over the course of a four-year study, researchers reported Friday in The Lancet journal.

In the trial, researchers randomly gave the TCV vaccine to half of over 28,000 healthy children in the south African nation of Malawi. The other half of the children received a meningitis vaccine.

Over the next four years, rates of typhoid incidence fell dramatically among kids who got the TCV shot. Just 24 children who got the vaccine developed typhoid, compared to 110 kids who didn’t receive it — a more than 78% efficacy rate.

Put another way, one case of typhoid was prevented for every 163 kids who got the TCV vaccine, the researchers said.

The shot appeared to work well regardless of a child’s age, and its effectiveness declined only slightly over time — about a 1.3% drop in efficacy per year, the investigators said.

“The newly published study supports the long-lasting impacts of a single shot of TCV, even in the youngest children, and offers hope of preventing typhoid in the most vulnerable children,” said study co-author Dr. Kathleen Neuzil. She’s a professor of vaccinology at the University of Maryland School of Medicine (UMSOM) in Baltimore.

According to background information from the researchers, typhoid is usually contracted from contaminated food or beverages. Its symptoms include nausea, fever and abdominal pain. Left untreated, the disease can prove fatal.

Over 9 million cases of typhoid are recorded worldwide each year.

The results of the new trial “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 alongside the study.

Based on the trial results, the Malawi government is now committed to vaccinating all children under the age of 15. Going forward, all babies will receive the Typbar TCV shot at the age of 9 months as part of their routine vaccinations.

“The research could not come at a more critical time, when Malawi and other African countries are struggling with climate change, extreme weather events and increased urbanization patterns, which are likely to contribute to increases in enteric diseases, including typhoid,” UMSOM Dean Dr. Mark Gladwin said in a university news release.