Washington DC [US], February 5 : The Pan American Health Organization (PAHO), a specialised agency of the United Nations, has issued an epidemiological alert highlighting a significant surge in measles cases throughout the Americas region during 2025 and the early part of 2026.
In its statement released on Wednesday, PAHO stressed the urgent need for member states to bolster routine surveillance and immunisation programmes. "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 organisation said.
According to the report, the Americas recorded 1,031 confirmed measles cases in just the first three weeks of 2026. For the full year of 2025, the total reached 14,891 confirmed cases.
The most severe outbreaks have been reported in North America, particularly affecting the United States, Mexico and Canada, where case numbers remain alarmingly high.
Measles, a highly contagious airborne virus, can infect up to nine out of ten unvaccinated individuals exposed to it. While symptoms typically resolve within weeks in most cases, the disease poses serious risks, especially to young children, potentially leading to severe complications such as ear infections, pneumonia, lung inflammation, or encephalitis, a brain swelling that may result in long-term issues including seizures and memory impairment.
The only effective prevention against measles is vaccination, commonly delivered through the MMR (measles, mumps and rubella) combination vaccine. Health authorities recommend the first dose for children before 15 months of age, with the second dose administered before age six.
Although the MMR vaccine is widely regarded as safe and provides lifelong protection, vaccination coverage has declined in some countries, including the United States, partly due to misinformation and unfounded claims. In the US, Health and Human Services Secretary Robert F Kennedy Jr has previously stated that the vaccine "wanes very quickly" and suggested associated health risks, assertions contradicted by experts and agencies like the US Centers for Disease Control and Prevention (CDC), which affirm that the vaccine is far safer than contracting measles itself.
The Infectious Diseases Society of America notes on its website, "There have been no deaths shown to be related to the MMR vaccine in healthy people."
In the United States, PAHO reported 171 new measles cases in the first three weeks of 2026, following 2,242 cases throughout 2025. A major ongoing outbreak in South Carolina has recorded 876 incidents in recent months, with 800 cases among unvaccinated individuals, 16 partially vaccinated, and 38 of unknown status.
Another significant outbreak in Texas between January and August produced 762 cases, resulting in two deaths among unvaccinated children and 99 hospitalisations.
The United States had achieved measles elimination status in 2000, meaning no sustained domestic transmission, though imported cases occasionally occurred. Mexico secured elimination in 1996 after a robust vaccination drive, and the entire Americas region was declared measles-free in 2016.
However, persistent outbreaks now threaten the elimination status of both the US and Mexico. Mexico reported the highest regional total in 2025 with 6,428 cases, and an additional 740 cases emerged in the first three weeks of 2026.
PAHO has indicated it will review the elimination status of the United States and Mexico during a virtual meeting scheduled for April 13.
Canada lost its measles elimination status in November after multiple outbreaks since October 2024. The country recorded 5,436 cases in 2025 and 67 in the opening three weeks of 2026. Regaining elimination requires halting transmission linked to current outbreaks for over one year.
PAHO's alert underscores the critical importance of sustained high vaccination coverage to reverse the resurgence and protect vulnerable populations across the region.