Chikungunya vaccine

A Chikungunya vaccine is a vaccine intended to provide acquired immunity against the chikungunya virus.

The most commonly reported side effects include headache, fatigue, muscle pain, joint pain, fever, nausea and tenderness at the injection site.

The first chikungunya vaccine was approved for medical use in the United States in November 2023.

Medical uses
The chikungunya vaccine is indicated for the prevention of disease caused by chikungunya virus in individuals 18 years of age and older who are at high risk of exposure to the chikungunya virus.

History
The safety of the chikungunya vaccine was evaluated in two clinical studies conducted in North America in which about 3,500 participants 18 years of age and older received a dose of the vaccine with one study including about 1,000 participants who received a placebo. The effectiveness of the chikungunya vaccine is based on immune response data from a clinical study conducted in the United States in individuals 18 years of age and older. In this study, the immune response of 266 participants who received the vaccine was compared to the immune response of 96 participants who received placebo. The level of antibody evaluated in study participants was based on a level shown to be protective in non-human primates that had received blood from people who had been vaccinated. Almost all vaccine study participants achieved this antibody level.

The US Food and Drug Administration (FDA) granted the application for the chikungunya vaccine fast track, breakthrough therapy, and priority review designations. The FDA granted approval of Ixchiq to Valneva Austria GmbH.

Legal status
In May 2024, the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Ixchiq, intended for the prevention of chikungunya disease in adults. The applicant for this medicinal product is Valneva Austria GmbH. Ixchiq was reviewed under EMA's accelerated assessment program. It contains the live attenuated chikungunya virus (CHIKV) Δ5nsP3 strain of the ECSA/IOL genotype. Ixchiq was approved for medical use in the European Union in June 2024.

Research
A phase-II vaccine trial used a live, attenuated virus, to develop viral resistance in 98% of those tested after 28 days and 85% still showed resistance after one year. However, 8% of people reported transient joint pain, and attenuation was found to be due to only two mutations in the E2 glycoprotein. Alternative vaccine strategies have been developed, and show efficacy in mouse models.

In August 2014, researchers at the National Institute of Allergy and Infectious Diseases in the USA tested an experimental vaccine using virus-like particles (VLPs) instead of attenuated virus. All of the 25 people participating in this phase I trial developed strong immune responses.

As of 2015, a phase II trial was planned, using 400 adults aged 18 to 60 and to take place at six locations in the Caribbean. In 2021, two vaccine manufacturers, one in France, the other in the United States, reported successful completion of phase II clinical trials.