At a glance
- Two chikungunya vaccines are available in the United States: a live-attenuated vaccine (IXCHIQ) and a virus-like particle vaccine (VIMKUNYA).
- The live-attenuated vaccine is licensed for adults aged 18 years and older. The virus-like particle vaccine is licensed for people aged 12 years and older.
- Vaccination should be considered for some travelers at higher risk of exposure to chikungunya virus and for some laboratory workers.
Overview
Two chikungunya vaccines are currently licensed and approved for use in the United States:
- The live-attenuated vaccine (IXCHIQ) is manufactured by Valneva and was the first chikungunya vaccine to be licensed by the Food and Drug Administration (FDA) in November 2023. The Advisory Committee on Immunization Practices (ACIP) first approved recommendations for use in U.S. travelers and laboratory workers in February 2024 and later revised traveler recommendations in May 2025.
- The virus-like particle vaccine (VIMKUNYA) is manufactured by Bavarian Nordic. The vaccine was licensed by FDA in February 2025 and ACIP approved recommendations for use in U.S. travelers and laboratory workers in May 2025.
Restricted use of live-attenuated (IXCHIQ) vaccine for people 60 years and older
ÐÇ¿ÕÓéÀÖ¹ÙÍø and FDA investigated five hospitalizations for cardiac or neurologic events following vaccination with IXCHIQ among older people in 2024 and 2025. This topic was discussed at the Advisory Committee on Immunization Practices (ACIP) meeting on April 16, 2025. We are also aware of of serious adverse events among people aged 62 to 89 years following use of IXCHIQ in other countries. the live-attenuated vaccine should not be used among people 60 years and older until these additional reports are further investigated.
Recommendations for travelers
The risk of chikungunya for most U.S. travelers is low. However, some travelers are at higher risk for infection based on their destination or duration of travel. Healthcare providers can use ÐÇ¿ÕÓéÀÖ¹ÙÍø's decision tree to help determine when chikungunya vaccination for travelers is appropriate.
Live-attenuated vaccine
- ACIP recommends the live-attenuated vaccine for people aged 18 years and older* traveling to a country or territory where a chikungunya outbreak is occurring.
- In addition, the vaccine may be considered for people aged 18 years and older* who are traveling or moving to a country or territory without an outbreak but with elevated risk for U.S. travelers if planning to stay for an extended period of time (e.g., 6 months or more).
*Age 65 years and older is a precaution for use of the live-attenuated vaccine. ÐÇ¿ÕÓéÀÖ¹ÙÍø and FDA also advise a pause on use of this vaccine for people aged 60 years and older while serious adverse events in older people are further investigated.
Virus-like particle vaccine
- ACIP recommends the virus-like particle vaccine for people aged 12 years and older traveling to a country or territory where a chikungunya outbreak is occurring.
- In addition, the vaccine may be considered for people aged 12 years and older who are traveling or moving to a country or territory without an outbreak but with elevated risk for U.S. travelers if planning to stay for an extended period of time (e.g., 6 months or more).
Recommendations for laboratory workers
ACIP recommends chikungunya vaccine, either the live-attenuated or virus-like particle vaccine, for laboratory workers with potential for exposure to chikungunya virus.
Laboratory work with chikungunya virus is generally restricted to Biosafety Level 3 (BSL-3) facilities and practices. A local institutional biosafety committee should undertake a risk assessment of the potential for exposure to chikungunya virus for each laboratory worker working with the virus. The committee should consider the type of work to be performed and biosafety level at which work will be conducted. Vaccination is not necessary for workers handling clinical samples who should routinely use standard practices for handling patient samples.
Precautions and contraindications
To minimize the risk of serious adverse events, healthcare providers should carefully observe contraindications and consider precautions for vaccination before vaccine administration.
Live-attenuated vaccine
- Contraindications: altered immune status, history of severe allergic reaction to any component
- Precautions: pregnancy*, breastfeeding, age 65 years and older
Virus-like particle vaccine
- Contraindications: history of severe allergic reaction to any component
- Precautions: altered immune status, pregnancy*
*If both vaccines are available, the virus-like particle vaccine would be preferred for pregnant women. This is based on general principles that vaccination with non-live vaccines is preferred over vaccination with live vaccines for pregnant women.
Contraindications
- Altered immune status due to immunodeficiency or immunosuppression from disease or medications such as immunomodulatory therapies.
- History of a severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine.
Precautions
Pregnancy
- Pregnant women should avoid the risk for chikungunya virus infection, if possible.
- In general, vaccination should be deferred until after delivery. However, when the risk of infection is high (e.g., during an outbreak) and exposure cannot be avoided, a healthcare provider and pregnant woman should discuss the risks of chikungunya virus infection and the potential benefits and risks of vaccination.
- If a pregnant woman chooses to be vaccinated, vaccination should generally be avoided during the first trimester (until 14 weeks gestation) and after the 36th week of gestation.
- If both the live-attenuated and virus-like particle vaccines are available, the virus-like particle vaccine would be preferred for pregnant women. Although there are no data, this is based on general principles that vaccination with non-live vaccines is preferred over vaccination with live vaccines for pregnant women.
Breastfeeding
- Breastfeeding women and their infants should avoid the risk for chikungunya virus infection, if possible.
- In the absence of data, breastfeeding is a precaution for vaccination. However, when the risk of infection is high and exposure cannot be avoided, a healthcare provider and a breastfeeding woman should discuss the health benefits of breastfeeding for the infant, the risks of chikungunya virus infection, and the potential benefits and risks of vaccination.
Age 65 years and older
- In general, vaccination with the live-attenuated vaccine should be avoided for people aged 65 years and older. Additionally, ÐÇ¿ÕÓéÀÖ¹ÙÍø and FDA advise a pause on use of this vaccine among people aged 60 years and older until serious adverse events in older people are further investigated.
- This precaution is based on investigations into reports of serious adverse events following vaccination with the live-attenuated vaccine among older people.
- However, the live-attenuated vaccine can still be offered if the benefit of protection through vaccination outweighs the risk for adverse reactions to vaccination. A healthcare provider and a person 65 years and older should discuss the risks of chikungunya virus infection and the potential benefits and risks of vaccination.
Contraindications
- History of a severe allergic reaction (e.g., anaphylaxis) to any component of the vaccine.
Precautions
Altered immune status
- Immunocompromised people, including those with an immunodeficiency or immunosuppression from disease or medications, might have a diminished immune response to the vaccine.
Pregnancy
- Pregnant women should avoid the risk for chikungunya virus infection, if possible.
- In general, vaccination should be deferred until after delivery. However, when the risk of infection is high (e.g., due to an outbreak) and exposure cannot be avoided, a healthcare provider and pregnant woman should discuss the risks of chikungunya virus infection and the potential benefits and risks of vaccination.
- If a pregnant woman chooses to be vaccinated, deferring vaccination until after the first trimester (after 14 weeks gestation) might be preferred.
- The vaccine should ideally be administered a minimum of 2 weeks before the expected date of delivery—preferably earlier—to allow for protection around the time of delivery.
- If both the virus-like particle and live-attenuated vaccines are available, the virus-like particle vaccine would be preferred for pregnant women. Although there are no data, this is based on general principles that vaccination with non-live vaccines is preferred over vaccination with live vaccines for pregnant women.
Side effects of vaccination
Reporting adverse events
Live-attenuated vaccine
Common adverse reactions following vaccination that occurred in more than 10% of vaccinated participants in clinical trials included tenderness, headache, fatigue, myalgia, arthralgia, fever, and nausea. The vaccine also caused severe or prolonged chikungunya-like adverse reactions in some people.
In addition, since licensure, several reports of serious adverse events following vaccination among people 65 years and older in the United States have been reported to VAERS. The adverse events included hospitalizations for cardiac (e.g., atrial flutter) or neurologic (e.g., meningitis) manifestations. Most of the patients had multiple underlying medical conditions before vaccination. Fortunately, most of the affected patients recovered within a few weeks. In May 2025, ACIP made age 65 years and older a precaution to vaccination with the live-attenuated vaccine. ÐÇ¿ÕÓéÀÖ¹ÙÍø and FDA also advised a pause in use for people aged 60 years and older while additional serious adverse events are investigated.
Virus-like particle vaccine
Common adverse reactions following vaccination that occurred in more than 10% of vaccinated participants aged 12–64 years in clinical trials included injection site pain, fatigue, headache, and myalgia. Common adverse reactions that occurred in more than 5% of vaccinated participants aged 65 years and older in clinical trials included injection site pain, fatigue, and myalgia.
Effectiveness and duration of protection
Live-attenuated vaccine
Clinical trial results indicated that vaccination resulted in an initial seroresponse rate of 99% at 4 weeks after vaccination that was maintained at 96% or higher for at least 3 years after vaccination. Data on additional longer-term seroresponse rates are still being gathered.
Virus-like particle vaccine
Clinical trial results indicated that vaccination resulted in seroresponse rates of 98% for people aged 12–64 years and 87% for people aged 65 years and older at 3 weeks after vaccination. At 6 months after vaccination, rates were 85% and 76% for the two age groups, respectively. Data on long-term seroresponse rates are still being gathered.
Administering the vaccine
Live-attenuated vaccine
- Administered intramuscularly
- Single 0.5mL dose
- Currently no recommendations for a booster dose
Virus-like particle vaccine
- Administered intramuscularly
- Single 0.8mL dose
- Currently no recommendations for a booster dose
