Situation Report #3: Measles in the Americas Region. 21 May 2026

Download	Between epidemiological week (EW) 1 and EW 19 of 2026 (ending on 16 May 2026), the Region of the Americas reported 20,332 confirmed measles cases from 16 countries and territories, including 25 deaths, representing a 276% increase compared to the same period in 2025. Mexico (10,817), Guatemala (6,209), the United States (1,893) and Canada (1,018) accounted for the majority (98%) of confirmed cases. During EW 17 and EW 18 of 2026, the Region of the Americas reported 1,241 new confirmed measles cases across eight countries and territories, representing a 24.5% decrease compared with the previous two-week period (EW15-16; 1,644 new cases). This decline was driven primarily by sustained reductions in Mexico and continued decreases in Canada. Peru was the main exception, with cases continuing to increase during this period, mostly concentrated in Puno. Trends in Guatemala should be interpreted with caution, given possible reporting delays or updates in recent weeks. The outbreak continues to disproportionately affect young children, with the highest incidence rates observed among infants under one year of age. Approximately two-thirds of confirmed cases have no documented history of measles vaccination3. The D8 genotype, DSId 9171 has been identified across multiple countries and remains the main genotype detected in the Region.