Children Also Need Access to Chikungunya Vaccines

Considering the significant risk chikungunya poses to all individuals living in or traveling to endemic areas in 2025, authorizing a preventive vaccine for children has become essential as international tourism rebounds.

Currently, there are two chikungunya vaccines available in the United States; however, neither is approved for use in children.

In line with realizing the public health need for people visiting Brazil, India, and other countries in 2025, Valneva SE today announced positive six-month antibody persistence and safety data for its Phase 2 clinical trial evaluating the safety and immunogenicity of two different dose levels of its single-shot chikungunya vaccine, IXCHIQ®, in 304 children.

Trial VLA1553-221's six-month results were in line with the initial data the Company reported for this trial in January 2025. A full dose (licensed IXCHIQ formulation and presentation) elicited a more robust immune response in children aged 1 to 11 years at Day 15 and Day 180 post-vaccination compared to a half dose.

Overall, the immunological response profile was consistent with what had been previously observed in adults and adolescents.

The strong immune response was confirmed in CHIKV-naïve children with a 96.5% seroresponse rate (full dose) at Day 180. VLA1553 was well tolerated in children aged 1 to 11 years, regardless of the dose or previous CHIKV infection. No safety concerns were identified.

The comparability of the VLA1553 doses tested in terms of safety and tolerability, along with the more pronounced immune response observed for the full dose in all age groups tested in children up to Day 180 post-vaccination, supports the selection of the full dose for use in this population.

Juan Carlos Jaramillo, M.D., Chief Medical Officer of Valneva, said in a press release, "The six-month persistence and safety data in children are aligned with the robust antibody response and safety profile we reported in adolescents after a single vaccination."

This trial is designed to support a pivotal Phase 3 study in children, which the Company anticipates initiating in the first quarter of 2026, to expand the product label to this age group.

Globally, chikungunya cases have been reported in over 100 countries.

Current outbreaks are occurring in the Indian states of Maharashtra and Telangana, as well as in the French Departments of La Réunion and Mayotte, and Argentina, Bolivia, Brazil, Paraguay, and Peru. These outbreaks have heightened the need to protect children from this mosquito-transmitted disease.

In the U.S., travel vaccines and services are offered at clinics and pharmacies in June 2025.