Chikungunya and Carnival 2026 Shouldn't Mix in Brazil

The Chikungunya virus (CHIKV) has been circulating in the Region of the Americas for decades, causing large epidemics throughout the tropics and subtropics.

In the Federative Republic of Brazil, the co-circulation of arboviruses such as Dengue and Zika, and overlapping disease symptoms, CHIKV infection may be underdiagnosed, according to a recent study's findings.

Current data indicate that over 238,000 CHIKV cases and 115 related fatalities have been reported in Brazil this year.

In November 2025, the European CDC Situation Update reported CHIKV cases across all regions (Centro-Oeste, Nordeste, Norte, Sudeste, and Sul) and in most federal units of the country.

The Centro-Oeste and Sudeste regions account for the highest number of cases in recent weeks, where Mato Grosso Do Sul, Minas Gerais, and São Paulo are the most affected federal units in 2025.

The ECDC writes that cases are expected to increase from November onwards, based on observed trends in 2024 and 2023.

As of November 19, 2025, the U.S. CDC reports an elevated chikungunya risk in Brazil.

These health agency analyses are of interest to international travelers planning to attend Carnival 2026 in cities such as Rio de Janeiro.

The CDC says chikungunya vaccination may be considered for people traveling to or moving to this location if they plan to stay for an extended period. In the United States, approved chikungunya vaccination services are offered at travel clinics and pharmacies.