The Pan American Health Organization (PAHO) on Wednesday issued an alert urging countries across the Americas to step up epidemiological surveillance and vaccination programs in response to a widening measles outbreak.
PAHO reported that during the first three weeks of 2026 an additional 1,031 measles cases were confirmed in seven countries, with the largest numbers recorded in Mexico and the United States. The agency noted that this figure represents a 43-fold increase compared with the 23 cases reported during the same period in 2025.
The agency said the rise in cases follows an elevated level of measles infections throughout 2025 compared with the previous five years, a trend that appears to be continuing into 2026. PAHO highlighted that Canada lost its measles elimination status in November after nearly three decades, citing the country's failure to contain a year-long outbreak; that loss also resulted in the Americas region losing its elimination status.
At the subnational level, PAHO pointed to a widening outbreak in South Carolina where officials reported 876 measles cases in the state. Local authorities warned that the outbreak could persist for weeks or months amid lagging vaccine uptake.
PAHO urged member states to prioritize strengthening surveillance and vaccination activities and to ensure a rapid and timely response to suspected cases. The agency specifically recommended reinforcing disease surveillance and laboratory testing capacity, closing immunity gaps through targeted vaccination campaigns, and responding quickly to suspected measles cases to limit further spread.
Among cases for which vaccination information was available, PAHO said 78% were not vaccinated and 11% had an unknown vaccination status. The agency emphasized that these gaps in routine immunization are fueling the current outbreaks.
PAHO's advisory frames its recommendations around three operational priorities: enhancing detection through surveillance and lab confirmation; closing immunity gaps by increasing vaccine coverage; and ensuring rapid response mechanisms are in place when suspected cases arise.
With confirmed cases concentrated in multiple countries and significant increases compared with early 2025, PAHO's call to action underscores both the urgency and the multifaceted nature of the response required to control transmission across the region.