30 May 2022
Diarrhoea is one of the most common diseases, globally, affecting children under five years of age. Although typically being a self-limiting condition in western civilisations, it can be a killer in low- and middle-income countries, where it is a leading cause of death and high morbidity for young children. Shigella and enterotoxigenic Escherichia coli (ETEC) are some of the most common pathogens that cause diarrhoea and there is presently no approved vaccine against them. Repeated infections with these bacteria can also have long-term negative effects on children’s growth and development.
The EVI-led SHIGETECVAX project, funded by the European Commission, has conducted a phase I clinical trial in Hungary of a combined Shigella/ETEC live attenuated vaccine candidate. The vaccine candidate, termed ShigETEC, is given orally (drinkable) and has been developed by Eveliqure Biotechnologies, an Austrian biotech company. ShigETEC is based on a genetically modified non-invasive Shigella vaccine strain, which lacks the bacterial surface coat comprised of dominant sugar antigens. Removal of the surface coat allows for the immune recognition of minor and highly conserved antigens, thereby driving a more robust and broader immune response. Additionally, the vaccine strain carries ETEC antigens expected to induce protective antibodies that inactivate diarrhoea-causing toxins.
The clinical phase I trial was performed as a two-stage, double-blind, randomized, placebo-controlled dose-escalation evaluation, and the results showed that the vaccine was well tolerated and safe across the different dose groups tested, with only minor and transient reactogenicity. ShigETEC induced robust systemic and mucosal immune responses against the Shigella strain that was used for the vaccine. Anti-ETEC toxin antibodies were also detected, primarily in a 4-times immunised cohort and correlated with toxin neutralizing capacity.
"The result of this clinical trial is highly encouraging and supports our ambitious goal to develop a vaccine that is affordable, can be given orally and protects against two of the deadliest diarrhoeal pathogens at the same time", said Ole Olesen, Executive Director at European Vaccine Initiative.
Following these promising data, a safety and immunogenicity study in adults and children from endemic areas is planned within the SHIGETECVAX project and will further inform about the potential of ShigETEC to reduce the burden of diarrhoeal diseases in children in low- and middle income countries.
Read full publication: https://www.mdpi.com/2076-393X/10/2/340/htm
This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 815568.