Chikungunya virus is circulating simultaneously across four distinct regions of the world, prompting the U.S. Centers for Disease Control and Prevention (CDC) to maintain Level 2 Travel Health Notices — “Practice Enhanced Precautions” — for Bolivia, Mayotte, Suriname, and Seychelles. An updated risk summary published by the health authority on April 16, 2026 consolidates current outbreak status, elevated-risk country designations, and vaccination guidance into a single reference for travelers and clinicians navigating an increasingly active transmission landscape.
Outbreaks Span Three Continents, Ten Countries Show Elevated Risk
The four active outbreak locations span South America, the Indian Ocean, and the French overseas territory of Mayotte near the Comoros archipelago. In Bolivia, transmission is concentrated in the Santa Cruz and Cochabamba Departments. The notices for Suriname, Seychelles, and Mayotte were posted between February and March 2026. Beyond these active outbreak zones, CDC has identified ten countries — Brazil, Colombia, India, Indonesia, Mexico, Nigeria, Pakistan, Peru, the Philippines, and Thailand — where U.S. travelers face elevated background risk even in the absence of a declared outbreak. Each of those countries has reported a median of one or more travel-associated cases annually in U.S. travelers over the past five years, with at least one laboratory-confirmed case.
Chikungunya is a mosquito-borne viral illness transmitted primarily by Aedes aegypti and Aedes albopictus mosquitoes, species with wide tropical and subtropical distributions. The virus has been identified in more than 100 countries. Symptoms typically begin three to seven days after an infected mosquito bite and most commonly include fever and severe joint pain. While most patients recover within a week, a subset experiences debilitating joint pain lasting months to years. There is no specific antiviral treatment. Populations at heightened risk for severe outcomes include newborns infected near the time of delivery, adults 65 years and older, and individuals with underlying conditions such as diabetes or heart disease.
New Single-Dose Vaccine Shows High Efficacy in Clinical Trials
A notable development in the chikungunya prevention landscape is the relatively recent availability of a licensed vaccine in the United States. VIMKUNYA, a virus-like particle vaccine manufactured by Bavarian Nordic, was licensed by the Food and Drug Administration in February 2025. The Advisory Committee on Immunization Practices (ACIP) approved recommendations for its use in April 2025. The vaccine is approved for individuals 12 years and older and is administered as a single 0.8 mL intramuscular dose. Clinical trial data showed seroresponse rates of 98 percent in participants aged 12 to 64 years at three weeks post-vaccination, declining to 85 percent at six months. For adults 65 and older, response rates were 87 percent at three weeks and 76 percent at six months. Long-term durability data are still being gathered.
CDC Recommends Vaccination for All Travelers to Outbreak Areas
CDC’s current recommendations call for vaccination of all eligible travelers heading to an area with an active chikungunya outbreak. Vaccination may also be considered for travelers planning extended stays — generally six months or longer — in any of the ten elevated-risk countries even without an active outbreak. The vaccine is also recommended for laboratory workers with potential exposure to chikungunya virus, who typically operate under Biosafety Level 3 conditions. Pregnant travelers warrant particular attention: CDC advises reconsidering travel to outbreak areas for those nearing delivery, as the virus can be transmitted from mother to newborn perinatally, with potentially severe consequences. In general, vaccination should be deferred until after delivery, though providers are advised to conduct individualized risk-benefit discussions when exposure cannot be avoided.
The most recent locally acquired case in the continental United States was reported in 2025, a reminder that returning viremic travelers can, under the right mosquito conditions, seed domestic transmission.
Sources and further reading:
Update on Chikungunya Risks to Travelers, Travel Alerts, Vaccine Recommendations in U.S.
Chikungunya Vaccine Information for Healthcare Providers
Chikungunya Vaccine Information – CDC
CDC Travel Notice — Chikungunya in Mayotte
CDC Travel Notice — Chikungunya in Suriname