Chikungunya Vaccine Produced 97% Seroresponse Rate After Two Years

Valneva SE today announced positive antibody persistence data twenty-four months after vaccination with a single dose of its chikungunya vaccine IXCHIQ®.

As reported on December 4, 2023, 97% of the 316 healthy adults still enrolled in a phase 3 study retained neutralizing antibody titers above the seroresponse threshold.

The persistence of antibodies in older adults aged 65 and above was as robust as in younger adults and even slightly higher in terms of geometric mean titers and seroconversion rates.

This outcome underscores the vaccine's potential to offer strong and lasting protection against chikungunya across different age groups.

Juan Carlos Jaramillo, M.D., Chief Medical Officer of Valneva, said, "We are very pleased about these twenty-four-month data, which confirm IXCHIQ®'s ability to induce a robust, long-lasting antibody response in both younger and older adults with a single vaccination."

"Being the world's first approved vaccine against chikungunya, each positive outcome further strengthens the defense against this significant and expanding public health threat."

These results from VLA1553-303 follow the completion of the pivotal Phase 3 study published in the Lancet in which a seroresponse rate of 96% six months after a single vaccination1 was reported.

Valneva was granted U.S. FDA approval for IXCHIQ in November 2023, and two marketing applications are currently under review by Europe and Canada, with potential approvals in mid-2024.

The U.S. CDC intends to review the use of IXCHIQ in 2024.

The World Health Organization says the chikungunya virus was identified in over 100 countries, and 340 related deaths have been reported in the past year.