Measles surges across the Americas as vaccination gaps widen

Measles has surged back across the Americas with alarming speed, turning a preventable disease into a cross-border warning for health systems, schools and travelers. The Pan American Health Organization reported 14,465 confirmed cases in the region in epidemiological weeks 1 through 12 of 2026, almost equal to the 14,503 cases recorded in all of 2025, when 32 people died.

Public health officials say the problem is not just more cases, but weaker protection. PAHO said roughly two-thirds of confirmed measles cases in the region had no documented history of measles vaccination, and its February 18 rapid risk assessment classified the overall threat in the Americas as very high, especially where coverage is low. The World Health Organization has also assessed the regional risk as high and warned that imported infections remain a concern when unvaccinated travelers move through active transmission zones.

The pattern is spreading across borders. PAHO identified the D8 measles lineage in multiple countries and linked it to outbreaks in at least 10 countries, a sign that the virus is circulating widely rather than flaring in isolated pockets. Jarbas Barbosa, the PAHO director, has stressed that the resurgence is serious but reversible if governments intensify vaccination campaigns and close immunity gaps. PAHO also reminded governments that the Americas was the first region to eliminate polio, rubella and congenital rubella syndrome, a milestone now threatened by slipping measles coverage.

The United States, Canada and Mexico are carrying much of the region’s caseload. The Centers for Disease Control and Prevention reported 1,792 confirmed U.S. measles cases as of April 23, with 93% outbreak-associated, 22 new outbreaks in 2026 and 10 cases among international visitors. Canada’s national surveillance dashboard showed 871 cases by April 11, and British Columbia health authorities said more than 95% of Canada’s 2025 and 2026 cases were tied to a multijurisdictional outbreak that began in New Brunswick in October 2024. Mexico had 8,901 confirmed cases by April 8, already above its 2025 total of 6,464, with Chihuahua and Jalisco among the hardest-hit states and more than 33.9 million vaccine doses administered in response.

The surge lands as the United States, Canada and Mexico prepare to host the World Cup this summer, raising the stakes for school districts, clinics, border health officials and travel planners. Measles can move fast through unvaccinated communities, and once coverage slips, the disease can return with little warning.