ETVAX vaccine candidate shows promise against enterotoxigenic E. coli diarrhea

University of Gothenburg reports first successful results of the oral, inactivated vaccine candidate ETVAX against enterotoxigenic E. coli diarrhea in a placebo-controlled phase I/II study in infants and children from 6 months to 5 years of age in Bangladesh.

All predefined primary endpoints for the study were achieved, showing that the vaccine candidate was safe and broadly immunogenic, stimulating immune responses to all key vaccine components.

Only a few mild to moderate adverse reactions were observed among participants; while the vaccine induced impressive serum and intestinal immune responses in young children and infants, with 80-100% of children 2-5 years of age and 50-80% of infants 6-11 months of age responding to all key vaccine antigens.

Giving the vaccine together with an adjuvant enhanced the magnitude, breadth and kinetics of the intestinal immune responses in infants. Results are presented in this week´s issue of The Lancet Infectious Diseases.

Enterotoxigenic E. coli (ETEC) bacteria are a primary cause of diarrhea, leading to substantial illness and death in children in low- and middle-income countries (LMICs) as well as in travelers to LMICs. Currently there is no ETEC vaccine available on the market for use in either children or travelers to ETEC high-risk areas, and ETEC vaccine development is a World Health Organization priority.

An oral ETEC vaccine candidate, ETVAX, was developed at University of Gothenburg in collaboration with Scandinavian Biopharma, Stockholm. ETVAX consists of inactivated E. coli bacteria expressing high levels of protective antigens and the ETEC-based B subunit protein LCTBA.

This clinical study examined the administration of ETVAX, given alone or together with different doses of an adjuvant, double-mutant heat-labile toxin (dmLT), to assess the vaccine's safety and immunogenicity in 450 children.

Descending age-groups of children 2-5 years, 1-2 years and 6-11 months were given two doses of vaccine in one of three fractionated doses levels (i.e., 1/8, 1/4 and 1/2) of a full adult dose with or without different doses (2.5-10 μg) of the dmLT adjuvant or buffer alone (placebo) as a drink two weeks apart in a double-blind manner.

In addition to safety analyses, immune responses were determined by measuring the amount of antibodies produced in the intestine (feces) as well as antibodies secreted by lymphocytes circulating in blood to the intestine.

The study was conducted at icddr,b in Dhaka, Bangladesh, as a collaborative effort between the Sahlgrenska Academy at University of Gothenburg, icddr,b, Scandinavian Biopharma, and the non-profit global health organization, PATH.

The results confirm and extend the promising data previously reported from ETVAX trials in Swedish and Bangladeshi adults. Based on the results of this trial, studies were initiated in September 2019 to further test safety, immune responses and protection of ETVAX (including dmLT) in African children 6-23 months of age. A study evaluating the protective efficacy of ETVAX in Finnish travelers to Africa will be completed by the end of the first quarter of 2020.

Journal reference:

Qadri, F. et al. (2019) Safety and immunogenicity of the oral, inactivated, enterotoxigenic Escherichia coli vaccine ETVAX in Bangladeshi children and infants: a double-blind, randomised, placebo-controlled phase 1/2 trial. The Lancet Infectious Diseases.


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
Measles vaccine more likely to be completely ineffective in children born by C-section