Promising Vaccine Candidate ETVAX Shows Efficacy Against Diarrheal Disease in Children

A latest vaccine, ETVAX, developed by Scandinavian Biopharma, is demonstrating promising results in the fight against diarrheal disease caused by enterotoxigenic Escherichia coli (ETEC) in young children. A recent phase 2b trial conducted in The Gambia has shown the vaccine to be safe and to induce an immune response, paving the way for potential widespread use in low-income countries.

What is ETEC and Why is it a Threat?

Enterotoxigenic E. Coli (ETEC) is a major cause of diarrheal disease, particularly in children under five years traditional in low-income nations. It is estimated to cause approximately 75 million diarrhea episodes and up to 42,000 deaths annually . ETEC causes severe diarrhea and dehydration, posing a significant health risk to vulnerable populations.

The Phase 2b Trial: Key Findings

The double-blind, placebo-controlled phase 2b trial in The Gambia involved 4,936 children aged six to 18 months. Participants received either ETVAX or a placebo at three timepoints: days 1, 15, and 90 . The study assessed safety, immunogenicity, and efficacy against moderate-to-severe ETEC-positive diarrhea (MSD-ETEC).

• Safety: Serious adverse events occurred in 1.0% of the ETVAX group and 1.3% of the placebo group, with no events directly linked to the vaccine .
• Immunogenicity: ETVAX increased antibody responses to ETEC colonization factors and heat-labile toxins in assessed children .
• Efficacy: While initial vaccine efficacy against the primary endpoint was 26.6%, it increased to 48.2% against MSD-ETEC regardless of co-pathogens, and significantly to 80.6% when excluding enteroparasitic pathogens . Vaccine efficacy against all MSD-ETEC reached 67.8% when vaccination started before nine months of age .

ETVAX: A Leading Vaccine Candidate

ETVAX is currently the most clinically advanced ETEC vaccine candidate . Researchers believe the need for an ETEC vaccine will grow, particularly in light of predictions for increased ETEC incidence due to a warming world. An effective ETEC vaccine could significantly reduce illness and deaths, improve child growth, decrease healthcare costs, and help curb antimicrobial resistance.

Next Steps

The study authors recommend progressing to a large, multicountry phase 3 trial to confirm ETVAX’s efficacy and support its introduction in high-burden settings . The Phase IIb trial in The Gambia was co-financed by the European and Developing Countries Clinical Trials Partnership Association (EDCTP) .