Measles is considered "eliminated" in America, meaning that outbreaks start from imported cases and end within 12 months. To be endemic, a disease must be present year-round. With a disease as contagious as measles, 95% vaccine coverage is needed to stop it from spreading.
America's worst measles outbreak in 30 years began in January 2025 in Texas and exceeded 800 cases across several states, killing three people. The hotspot was a Mennonite community in Gaines County, Texas, where only 81% of children starting school had received the MMR vaccine (which protects against measles, mumps and rubella). More than 400 cases were reported in Gaines County alone.
In the 2022-24 school years, two-thirds of counties (in the 37 states reporting county-level data) had MMR rates below 95%, according to researchers from Johns Hopkins University. Around a third of those below-threshold counties had been above 95% in the 2017-20 school years. Wisconsin, among the most permissive states for vaccine exemptions, had no county with an MMR rate above 85%.
In 2019 researchers at Emory University estimated that responding to a single measles case can cost $142,000.
Measles was eliminated from the Americas in 2016, the first region to manage a year without sustained transmission, but it returned in 2017 via Venezuela. The current hemisphere-wide outbreak began at a Mennonite wedding in Canada in October 2024 attended by a guest from Thailand. By April 25th 2026 PAHO had recorded 18,352 confirmed cases across the Americas in 2026, after 14,503 in 2025, with at least 45 deaths so far—mostly children. Most cases are in Mexico and Guatemala. Mexico's coverage for the second measles dose fell from 96% in 2014 to under 70% by 2024, and the government has since launched an emergency drive of around 30m doses between January 2025 and March 2026. The 2026 World Cup, starting June 11th and projected by FIFA to draw 5.5m fans, raises further risks. Only 19 of PAHO's 35 countries have an electronic immunisation registry; Uruguay was the first Latin American country to introduce one.
A study published in JAMA in April 2025 estimated that if childhood vaccination rates remain unchanged, measles will probably become endemic in America again after two decades—with an estimated 850,000 cases and around 850 deaths over 25 years. If the MMR rate in each state falls by a further 10%, endemic transmission would arrive sooner, with 11m cases and around 11,000 deaths in the same period.
I've known him as a man, as an adolescent and as a child -- sometimes on the same day.