Situation Report No.1: Measles in the Region of the Americas. 15 April 2026

 Between epidemiological weeks (EW) 1 and EW 14 of 2026, countries in the Region of the Americas reported 15,366 confirmed measles cases1. In 2025, 14,767 measles cases were reported, including 32 deaths. This follows a marked rise in cases during 2025, with continued acceleration observed in early 2026. 

Genotyping information indicate that the D8 lineage has been identified across multiple countries and is associated with outbreaks in at least ten countries, suggesting widespread circulation of this strain in the Region. 

The highest number of cases in 2026 have been reported in Mexico (n= 8,655), Guatemala (n= 4,109), the United States of America (n= 1,706), and Canada (n= 789), with ongoing transmission documented in Bolivia and other countries across the Region. 

All age groups are affected; however, the highest number of cases has been reported among children, particularly those aged 1–9 years, followed by children and adolescents aged 10–19 years. Incidence rates are highest among children under one year of age. 

A substantial proportion of cases occur among unvaccinated individuals, with available data indicating that approximately two-thirds of confirmed cases have no documented history of measles vaccination.