Valneva's chikungunya shot keeps antibody response in most adults at year five

Valneva has released long-term immunogenicity data for IXCHIQ, its one-dose chikungunya vaccine, announced on 10 November 2026. The company reports that 94% of the 221 healthy adults who could be assessed in trial VLA1553-303 still had neutralising antibodies at or above the level the study counts as a vaccine response, five years after receiving the shot.

Valneva also said that adults aged 65 and over responded similarly to those aged 18 to 64. The company's summary gives no further detail on the age-group comparison and does not discuss revenue, pricing or supply.

As context, durability data of this kind are generally used to judge how long immune responses last after a single administration. Antibody levels are a stand-in for protection, not a direct measure of it. The summary does not say whether the findings bear on booster policy or on the length of protection.

Valneva also pointed to a campaign in Brazil that vaccinated nearly 80,000 adults, which it says is meant to underpin studies of the product after launch. The trial will keep following participants for up to ten years, so more data are expected.