Situation Report #14: Measles in the Americas Region. 22 October 2026

Summary of the situation

Between epidemiological week (EW) 1 and EW 41 of 2026 (which ended on 17 October 2026), the Region of the Americas reported 56,753 confirmed cases of measles in 17 countries and territories, representing a 4.8-fold increase compared with the same period in 2025. Guatemala (34,535), Mexico (13,691), the United States (4,410), Peru (2,698), and Canada (1,124) account for the vast majority (99.5%) of confirmed cases (Map 1). A total of 81 deaths has been reported, including 53 in Guatemala, 23 in Mexico, three in the United States of America, one in Peru and one in Bolivia. 

During EW 39 and EW 40 of 2026, the Region of the Americas reported 643 new confirmed cases of measles in six countries and territories, representing a 32% decrease compared with the previous two-week period (EW 37–38; 946 new cases, including 259 retrospectively reported since the last Regional Situation Report) (Figure 1). Of the 643 new confirmed cases reported during EW 39–40, the United States accounted for 320, followed by Guatemala 211, Peru with 68, Mexico with 39, Canada with three, and Bolivia with two2. 

Despite declining transmission in some countries of the Americas, with Rt estimates below 1 (Table 3), persistent low-level transmission may continue through sporadic and hard-to-detect chains of infection. This "drop-by-drop" transmission pattern can sustain virus circulation for more than 12 months, delaying outbreak closure and increasing the risk of re-establishment of endemic transmission, which could ultimately jeopardize a country's measles-free status.