This Chikungunya Vaccine is Effective for Adolescents and Adults

The U.S. CDC's Advisory Committee on Immunization Practices announced last week that double-blind, randomized, placebo-controlled Phase 3 clinical trials are now the new standard for vaccine approvals in the United States.

With today's announcement, a chikungunya vaccine for adolescents meets this new standard.

The Lancet Infectious Diseases has published the final Phase 3 results of Valneva SE's chikungunya vaccine for adolescents, representing a significant advancement in the fight against this rapidly spreading disease.

Published on December 8, 2025, the study demonstrates a strong and sustained immune response one year after a single dose of the IXCHIQ® vaccine. It also confirms that the vaccine was well-tolerated throughout the trial.

The VLA1553-321 trial marks two significant firsts for the industry: it is the first clinical trial conducted in an endemic region, specifically Brazil, where outbreaks have been detected for over a decade, and the first to include participants who had previously been infected with the chikungunya virus.

These researchers wrote, 'To our knowledge, VLA1553 is the first approved vaccine to induce robust and sustained immune responses against chikungunya virus, and it has been licensed with the indication to prevent the disease caused by the chikungunya virus in adults.'

'VLA1553 was generally safe and induced seroprotective titres up to 12 months in nearly all adolescents, with favourable safety data in those who were seropositive.'

'The data support the use of VLA1553 for the prevention of disease caused by the chikungunya virus among adolescents and in endemic regions.'

This study was conducted in collaboration with the Instituto Butantan in Brazil and was funded by the Coalition for Epidemic Preparedness Innovations, with additional support from the EU Horizon 2020 program.

The CDC says some travelers at higher risk of exposure to the chikungunya virus should consider getting vaccinated before their trip to an endemic area, including countries in the Americas, such as Cuba, and southern France. 

Talk to your healthcare provider about chikungunya vaccines, which are available in the U.S., commercially offered at travel clinics and pharmacies.