The Pan-American Health Organization (PAHO) has announced that the Americas region has lost its status as free from endemic measles transmission. This decision follows the findings of PAHO’s Regional Commission for Monitoring and Re-verification of Measles, Rubella, and Congenital Rubella Syndrome Elimination, which convened in Mexico City from November 4 to 7, 2025, to assess the epidemiological situation in the region. The commission confirmed that endemic measles transmission has re-emerged in Canada, where the virus has been circulating for at least twelve months. This marks a significant setback for the Americas, which was the first region globally to eliminate measles twice. All other countries in the region retain their elimination status for now. PAHO Director Dr. Jarbas Barbosa emphasized that while this loss is a setback, it is reversible. He stressed that as long as measles persists globally, the region remains at risk of reintroduction and spread among unvaccinated or under-vaccinated populations. With political will, regional cooperation, and sustained vaccination efforts, transmission can be interrupted, and the shared success of elimination restored. As of November 7, 2025, 12,593 confirmed measles cases have been reported across ten countries, with 95% of cases concentrated in Canada, Mexico, and the United States. This represents a thirtyfold increase compared to 2024. Tragically, 28 deaths have been recorded, with 23 in Mexico, 3 in the U.S., and 2 in Canada. Active outbreaks are ongoing in Canada, Mexico, the U.S., Bolivia, Brazil, Paraguay, and Belize, primarily driven by imported cases. Most infections occur in under-vaccinated communities, with 89% of cases involving unvaccinated or vaccination-status-unknown individuals. Children under one year old are the most affected, followed by those aged one to four. The Canadian outbreak began in October 2024 in New Brunswick and spread nationwide, with over 5,000 confirmed cases. While new cases are declining, transmission persists in Alberta, British Columbia, Manitoba, and Saskatchewan. Measles, one of the most contagious viruses, can infect up to 18 people per case and lead to severe complications such as pneumonia, encephalitis, blindness, and death. Outbreaks also strain healthcare systems. Vaccination remains the most effective tool against measles, having prevented an estimated six million deaths in the Americas over the past 25 years and 15 million globally in the last 50 years. However, the regional coverage rate for the second dose of the MMR vaccine was only 79% in 2024, well below the 95% threshold needed to prevent outbreaks. PAHO continues to support countries in strengthening surveillance, laboratory diagnostics, outbreak response, and vaccination campaigns. Experts have been deployed to Mexico, Argentina, and Bolivia, while the organization closely monitors Belize, Brazil, and Paraguay. Dr. Barbosa urged countries to redouble their efforts, emphasizing that every prevented outbreak and stopped infection saves lives. The commission recommended intensifying vaccination campaigns, enhancing electronic immunization registries, sustainably funding laboratory capacity, and conducting PCR tests for suspected cases with negative IgM results. The Americas have previously regained measles-free status after temporary losses in Venezuela (2018) and Brazil (2019) through coordinated regional action. To regain the status, a country must demonstrate no endemic transmission for at least twelve consecutive months, supported by vaccination, surveillance, and outbreak response data. Canada is now implementing an action plan within PAHO’s regional framework to increase vaccination rates, strengthen monitoring systems, and respond swiftly to new outbreaks. Dr. Barbosa concluded, ‘Collaboration, solidarity, and science are stronger than any virus. When we work together, we protect the health and lives of all people in the Americas.’