BERGEN, Norway, July 7 (World Daily Times) — An experimental oral vaccine against a major cause of childhood diarrhea has shown early promise in a phase 2b trial in The Gambia, raising the possibility of added protection for young children if larger studies confirm the results.
The vaccine, ETVAX, targets enterotoxigenic Escherichia coli, or ETEC, a bacterium that causes severe diarrhea in low-income settings and travelers’ diarrhea, according to a 2025 review in PMC.
In the randomized, placebo-controlled study published in The Lancet Infectious Diseases, about 5,000 children ages 6 to 18 months received the vaccine or a placebo. The trial found no vaccine-related serious adverse events and showed that the children developed antibodies against ETEC.
The results were mixed but encouraging. Researchers reported 26.6% protection in the study’s main analysis, 48.2% protection against moderate-to-severe ETEC diarrhea when co-infections were included, and 80.6% protection when children with certain intestinal parasites were excluded.
Protection was also stronger when vaccination began before 9 months of age, at 67.8%, and the study found 21% protection against moderate-to-severe diarrhea from any cause. The authors called the findings the first demonstration of protective efficacy for ETVAX in young children at risk and said the results support a larger, multicountry phase 3 trial.
A 2025 review in PMC said no licensed ETEC vaccine is available for human use.
