Vaccine company Valneva SE (Nasdaq:VALN) (Euronext Paris:VLA) and LimmaTech Biologics AG, a clinical-stage biotech company, announced on Wednesday the start of a Phase 2 clinical trial to assess the safety and immunogenicity of their tetravalent Shigella vaccine candidate, S4V2, in infants.

The first participant has been vaccinated in this randomised, controlled and blinded study being conducted in Kenya.

S4V2 is currently the most clinically advanced tetravalent bioconjugate vaccine candidate targeting shigellosis, a leading cause of fatal diarrhoeal disease globally. Each year, Shigella is estimated to cause up to 165 million infections, including over 62 million in children aged under five.

The trial, known as S4V02, is planned to involve approximately 110 nine-month-old infants who will receive two doses of one of two vaccine strengths or a control vaccine. LimmaTech is sponsoring and conducting the study, which is funded by the Gates Foundation, with results expected in the second half of 2025.

This Phase 2 infant trial complements an ongoing Phase 2b controlled human infection model (CHIM) study initiated in November 2024 in healthy adult volunteers. The CHIM study is part of a staggered development approach aimed at generating early efficacy data before advancing to Phase 3 trials.

The US Food and Drug Administration has granted Fast Track designation to S4V2, recognising its potential to address a serious health threat and a significant unmet medical need.