Chikungunya Vaccination Could Save 73 Lives During an Outbreak

With Chikungunya virus transmission occurring in approximately 100 countries in Africa, Asia, and the Americas and significant outbreaks reported in May 2025, researchers have identified an effective method to reduce this mosquito-transmitted disease's impact on local communities.

The findings from a new study suggest that the newly approved chikungunya vaccine represents an important new tool for controlling outbreaks.

Published by the journal Nature Medicine on May 1, 2025, these researchers stated Valneva SE's IXCHIQ® chikungunya vaccine is now licensed and available in various countries; however, it remains uncertain whether it could be effectively deployed during outbreaks to reduce the health burden.

In this modeling seroprevalence study, they examined an epidemic in the Republic of Paraguay to reconstruct the dynamics of epidemic transmission, providing a framework to assess the theoretical impact of the vaccine if it had been available.

The study's estimates indicated that 33% (95% confidence interval (CI) 30.1–36.0%) of the population was infected during the outbreak.

The surveillance system identified only 6.3% (95% CI 5.8–6.9%) of infected people, with a mean infection fatality ratio of 0.013% (95% CI 0.012–0.014%).

They found that a disease-blocking vaccine with 75% efficacy, if administered to 40% of individuals aged 12 years and older over three months, could have prevented approximately 34,200 cases (95% CI 30,900–38,000), accounting for 23% of all cases, and 73 deaths (95% CI 66–81).

Moreover, if the IXCHIQ vaccine had also prevented infections, up to 88% of cases could have been avoided.

These researchers wrote, 'These findings suggest that the vaccine represents an important new tool for controlling outbreaks.'

Based on various findings, France's La Réunion Department is administering IXCHIQ in May 2025 to reduce its chikungunya outbreak.

Recently, studies have supported the use of vaccines to prevent chikungunya disease.

On January 20, 2025, Valneva reported IXCHIQ showed a sustained 98.3% sero-response rate one year after a single vaccination.

And the Lancet Infectious Diseases published results from a phase 3b study, concluding that after a single dose of IXCHIQ, chikungunya virus-neutralizing antibodies were detected for up to two years.

As of May 3, 2025, IXCHIQ is commercially available in the United States and is offered at various travel clinics and pharmacies. It is recommended by the U.S. CDC for most adults when visiting outbreak areas.