Measles Resurgence in Americas Driven by Large U.S. Outbreak

Overview

• The United States has recorded the largest measles outbreak in decades in 2026, with more than 4,400 confirmed cases and three deaths reported to health authorities.
• The Pan American Health Organization says the Americas have seen a regional surge in 2026 with more than 55,000 cases and dozens of deaths, signaling spread beyond isolated hotspots.
• Brazil has reported 61 mostly imported cases this year but retains its elimination status and is intensifying rapid case investigation, isolation, contact vaccination and large supplementary dose campaigns in states such as São Paulo and Amazonas.
• Brazilian immunization officials and experts link the U.S. surge to falling MMR coverage among schoolchildren and to recent U.S. policy changes that separated the combined MMR vaccine and reduced recommended childhood immunizations, which have increased public confusion and hesitancy.
• Health authorities warn the response is costly and that infants and vulnerable communities face higher risk, so they stress the need for at least 95% homogeneous MMR coverage to prevent re‑establishment of sustained transmission.