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The sharp increase in measles cases in the Americas Region during 2025 and early 2026 is a warning sign that requires immediate and coordinated action by Member States. The Pan American Health Organization / World Health Organization (PAHO/WHO) urges Member States to prioritize strengthening routine surveillance and vaccination activities, and to ensure a rapid and timely response to suspected cases. The implementation of active community, institutional, and laboratory searches for early case identification, as well as developing complementary vaccination activities aimed at closing immunity gaps is also recommended.
Global summary
According to monthly data on measles and rubella surveillance published by the World Health Organization (WHO), between 1 January 2025 and 1 January 2026, a total of 552,699 suspected cases of measles were reported in 179 Member States across the six WHO regions, of which 247,623 (44.8%) were confirmed1. Twenty-eight percent of cases were reported in the WHO Eastern Mediterranean Region, followed by the WHO African Region with 25% of cases and the WHO European Region with 22% of cases (Figure 1) (1).
Summary of the situation in the Americas Region
In 2025, between epidemiological week (EW) 1 and EW 53, 14,891 cases of measles were confirmed in the Americas Region, including 29 deaths, of which 22 (73%) occurred in indigenous populations (2). Cases were reported by Argentina (n= 36 cases), Belize (n= 44 cases), the Plurinational State of Bolivia (n= 597 cases), Brazil (n= 38 cases), Canada (n= 5,436 cases2 , including two deaths), Costa Rica (n= 1 case), El Salvador (n= 1 case), the United States of America (n= 2,242 cases, including three deaths), Guatemala (n= 1 case), Mexico (n= 6,428 cases, including 24 deaths), Paraguay (n= 49 cases), Peru (n= 5 cases), and Uruguay (n= 13 cases) (Table 1)(Figure 2) (3-21). This total represents a 32-fold increase compared with the 466 measles cases reported in 2024 (2). Compared with the historical record of measles in the Region, the number of confirmed measles cases in 2025 was the highest since 2019, which was the year with the highest number of cases in the last 22 years (n= 23,269) (Figure 3) (22-23).
In 2026, between EW 1 and EW 3, 1,031 cases of measles were confirmed in the Americas Region, with no deaths reported. The cases were reported by Bolivia (n= 10 cases), Canada (n= 67 cases), Chile (n= 1 case), the United States of America (n= 171 cases), Guatemala (n= 41 cases), Mexico (n= 740 cases), and Uruguay (n= 1 case) (Table 1) (3-21). This total represents a 45-fold increase compared with the 23 measles cases reported during the same period in 2025 (2, 25).