Valneva SE announced positive three-year antibody persistence data for its single-shot chikungunya vaccine, IXCHIQ. The data, collected from an ongoing trial, demonstrate that 96% of healthy adults maintained neutralizing antibody titers above the seroresponse threshold three years after vaccination. This finding supports the potential for long-term protection against chikungunya following a single dose, which is particularly crucial in low- and middle-income countries where vaccine access is often limited.
The study, VLA1553-303, which received funding from the Coalition for Epidemic Preparedness Innovations (CEPI) and the European Union’s Horizon Europe program, followed 278 healthy adults. The results showed that antibody persistence in older adults (65+) was comparable to that in younger adults (18-64) in terms of geometric mean titers (GMTs) and seroresponse rates (SRRs).
Long-Term Safety Profile
Long-term safety data were also collected, monitoring ongoing Adverse Events of Special Interest (AESI) and new-onset Serious Adverse Events (SAEs). According to the Clinical Trial Protocol, safety data collection concluded at two years post-vaccination, and the latest analysis did not include a further safety evaluation. No new safety concerns were reported during the two-year follow-up, and no AESIs were ongoing at the time of participant enrollment in the trial.
Expert Commentary
"We are extremely pleased about these three-year data which further highlight IXCHIQ’s differentiated product profile and ability to induce a robust, long-lasting antibody response in both younger and older adults with a single vaccination," said Juan Carlos Jaramillo M.D., Chief Medical Officer of Valneva. He emphasized the importance of long-term protection against mosquito-borne diseases, especially in regions with limited vaccine access.
Regulatory Landscape and Market Access
IXCHIQ is the world’s first and only licensed chikungunya vaccine, currently approved in the U.S., Europe, and Canada for individuals 18 years and older. Valneva has recently submitted label extension applications to the U.S. FDA, EMA, and Health Canada to potentially extend the vaccine's use to adolescents aged 12 to 17 years. These applications include the two-year antibody persistence data for potential addition to the product label.
The vaccine was launched in the U.S. in March 2024, following recommendations from the U.S. Advisory Committee on Immunization Practices (ACIP) and the CDC. Launches in France and Canada are also underway. Valneva anticipates marketing authorization in Brazil by the end of the year and has expanded its partnership with CEPI to support broader access to the vaccine in LMICs.
About Chikungunya
Chikungunya is a mosquito-borne viral disease transmitted by infected Aedes mosquitoes. It causes fever, severe joint and muscle pain, headache, nausea, fatigue, and rash. The joint pain can be debilitating and persist for weeks to years. Since its re-emergence in 2004, the virus has been identified in over 110 countries across Asia, Africa, Europe, and the Americas. Between 2013 and 2023, over 3.7 million cases were reported in the Americas, with a significant economic impact. The WHO has recognized chikungunya as a major public health problem, particularly as climate change expands the geographic range of mosquito vectors.
