PAHO assesses risk of measles spread as very high ahead of religious mass gatherings in the Americas

Vaccination gaps and increased population movement could facilitate further transmission, underscoring the need for stronger vaccination and surveillance efforts

Washington, D.C., 9 October 2026 (PAHO) — With several religious mass gatherings in South America expected to increase national and international travel across the Americas in the coming months, the Pan American Health Organization (PAHO) is urging countries to strengthen vaccination, surveillance and rapid response measures as the risk of measles spread across the Region remains very high.

The warning comes in a new PAHO regional risk assessment released amid ongoing outbreaks, persistent gaps in vaccination coverage and the detection of measles cases in new geographic areas. The assessment updates PAHO’s regional evaluation of 5 August 2026, with a specific focus on risks associated with upcoming religious mass gatherings in South America and their potential implications for the Region of the Americas.

“Measles is highly contagious, and we are seeing the consequences of gaps in vaccination coverage across the Americas,” said Dr. Jarbas Barbosa, PAHO Director. “People need to protect their children with the very effective and safe measles, mumps and rubella (MMR) vaccine, and countries have to close immunity gaps, strengthen surveillance and ensure that they can detect and respond rapidly to cases, particularly as increased travel and large gatherings create more opportunities for the virus to spread.”

According to the latest PAHO data, 55,792 confirmed measles cases and 77 deaths were reported in 17 countries and territories in the Region between 4 January and 3 October 2026. This represents a 4.8-fold increase in cases compared with the same period in 2025. 

Measles cases have also increased globally in 2026, increasing the likelihood of imported cases through international travel and onward transmission in communities with low immunity.