Each year, tens of thousands of children under five dies from diarrheal disease caused by enterotoxigenic Escherichia coli (ETEC), primarily in low-income countries. A new ETEC vaccine has shown promising results in reducing the risk of severe illness. The study was conducted in The Gambia in collaboration with the University of Gothenburg.
The findings, published in The Lancet Infectious Diseases, are based on a randomized, placebo-controlled trial in which approximately 5,000 children aged 6 to 18 months were randomly assigned to receive either the oral vaccine ETVAX or a placebo. The children were followed for up to two years, with regular health assessments and sample collection. ETVAX was administered orally in three doses.
The vaccine reduced the risk of severe ETEC disease by 48 percent. Protection was even higher (80 percent) when children carrying intestinal parasites that can also cause diarrhea were excluded.
Importance of early vaccination
The study underscores the importance of vaccinating children early. Among children vaccinated before nine months of age, protection reached 68 percent, compared with 48 percent in the overall age group. The vaccine also reduced the risk for severe diarrhea from any cause by 21 percent, similar to the effect observed with rotavirus vaccines, which are currently administered to approximately 40 million children in low- and middle-income countries through UNICEF.
No vaccine-related serious adverse events were observed among the children in the study, and the vaccine generated clear immune responses to the bacterial factors that cause disease.
After evaluating the results from the study in The Gambia, along with earlier ETVAX trials, the European Medicines Agency (EMA) supports advancing ETVAX into a multinational Phase 3 efficacy trial. This marks the final and most extensive stage of vaccine development.
Breakthrough After Years of Research
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ETVAX is the product of several decades of research at the University of Gothenburg, led by Ann-Mari Svennerholm and her research group in collaboration with the Swedish biotechnology company Scandinavian Biopharma. The vaccine has been evaluated across different age groups and countries in a stepwise development program before the current study was conducted in Africa.
"For many years, we have worked to develop a vaccine that can protect the youngest children, where the need is greatest," says Ann-Mari Svennerholm, senior researcher and professor of infection and immunity at the Sahlgrenska Academy at the University of Gothenburg. "The results indicate that the vaccine has great potential and provide a solid foundation for an international Phase 3 efficacy trial in multiple countries."
