Vaccine Candidate Protects People Against Salmonella Paratyphi A

A recent Oxford University-led study demonstrated that an oral live-attenuated vaccine, CVD 1902,  provided significant protection against S. Paratyphi A infection in adults, without any safety concerns.

This phase 2b study is essential as enteric fever, caused by Salmonella Typhi and Salmonella Paratyphi, leads to more than 100,000 deaths and over 8 million disability-adjusted life years each year. Around 30% of cases —over 2 million annually —are caused by S. Paratyphi A, for which no vaccine is currently available.

According to the U.S. CDC, most people in the United States with these illnesses (Typhoid fever and paratyphoid fever) are infected while traveling internationally.

Professor Sir Andrew Pollard, Director of the Oxford Vaccine Group and co-senior author, commented in a press release on October 30, 2025, "We are in a constant fight against bacterial infections, like paratyphoid, that threaten the lives of children in some of the most resource-poor regions of the world."

"This study provides hope that this important disease could be controlled by vaccination if the same effects can be obtained in real-life conditions in those communities."

The research was funded by the UK Medical Research Council and the National Institute for Health and Care Research (NIHR) Oxford Biomedical Research Centre, with collaboration from Bharat Biotech International Ltd. and the University of Maryland, where the vaccine was originally engineered.

The paper, "Safety, Efficacy, and Immunogenicity of a Salmonella Paratyphi A Vaccine," by McCann et al., was published in The New England Journal of Medicine.