Measles Surges Across the Americas as 2026 World Cup Nears

The line at the public clinic in Guadalajara snakes past a poster advertising next summer’s World Cup match at the city’s gleaming new stadium. Toddlers fidget on their parents’ laps. Teenagers in soccer jerseys scroll on their phones. A nurse, masked again for the first time in years, calls out the next name for an overdue measles shot.

In the region that once declared measles eliminated, health workers in Mexico, the United States and Canada are racing to contain a virus many people assumed was gone — just as they prepare to welcome hundreds of thousands of international visitors for the 2026 FIFA World Cup.

PAHO issues alert as cases spike

On Feb. 3, the Pan American Health Organization issued an epidemiological alert warning of a sharp rise in measles across the Americas and urging governments to strengthen vaccination, surveillance and rapid outbreak response. The numbers behind the warning mark a dramatic reversal for a region long seen as a vaccine success story.

In 2025, 13 countries in the Americas reported 14,891 confirmed measles cases and 29 deaths, according to PAHO. That is a 32-fold jump from the 466 cases recorded in 2024. During the first three weeks of 2026 alone, countries reported 1,031 cases — 43 times more than in the same period a year earlier.

Mexico, the United States and Canada together account for the bulk of the surge. Mexico reported 6,428 cases and 24 deaths in 2025, the highest national death toll in the region, followed by Canada with 5,436 cases and two deaths, and the United States with 2,242 cases and three deaths. In early 2026, Mexico has already logged 740 cases, the U.S. 171 and Canada 67.

“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,” PAHO said in its alert.

A “measles-free” status lost—and what elimination means

The warning lands less than three months after PAHO confirmed that endemic measles transmission had been reestablished in Canada, ending the Region of the Americas’ status as measles-free. The Americas first achieved elimination in 2016, after a 22-year vaccination drive, and briefly regained it in 2024 after Brazil and Venezuela interrupted earlier outbreaks.

Elimination, however, does not mean the virus disappears entirely. It is defined as the absence of continuous domestic transmission for at least 12 months in the presence of strong surveillance. Imported cases and small outbreaks can still occur — and, public health officials now say, can quickly spiral if vaccination coverage slips.

Vaccination coverage slips below outbreak-prevention threshold

By 2024, that is exactly what had happened. PAHO estimates that routine coverage with the first dose of measles-containing vaccine (usually given as the measles-mumps-rubella shot) across the Americas stood at 89%, below the 95% threshold widely considered necessary to prevent outbreaks of a virus as contagious as measles. Coverage with the second dose was 79%. Only about one-third of countries and territories in the region reached at least 95% for the first dose, and just one-fifth did so for the second.

Roughly 1.5 million children in the Americas did not receive any measles-containing vaccine in 2024.

“Most of the people who are getting sick did not receive the vaccine they needed as children,” said a PAHO epidemiologist who has worked on regional measles campaigns. Among confirmed cases with vaccination information in 2025 and early 2026, PAHO found that 78% were unvaccinated and another 11% had unknown vaccination status.

The highest incidence rates are in infants younger than 1 year old, who are too young to be fully vaccinated, followed by children ages 1 to 4 and 5 to 9. At the same time, the largest share of total cases falls among adolescents and young adults — cohorts who missed doses during years of eroding coverage and pandemic-era health service disruptions.

Outbreaks spread across borders, fueled by under-vaccinated pockets

The current wave is not limited to any single country. Bolivia recorded 597 cases in 2025. Belize, Paraguay, Uruguay, Guatemala, Argentina, Peru and Brazil reported smaller but significant outbreaks. But several of the most intense flare-ups share a common feature: clusters of low vaccination in specific communities.

In Mexico, officials have traced a major outbreak to a Mennonite community with very low vaccination rates in the western state of Jalisco, according to local and international reports. From there, the virus spread into surrounding towns and cities. By early this year, Jalisco alone had reported more than a thousand confirmed cases and thousands of suspected infections, prompting the state to issue a health alert, suspend classes in some schools and temporarily reinstate mask mandates in classrooms.

The national government has deployed thousands of health workers, set up roughly 2,000 new vaccination modules and opened temporary immunization stations at bus terminals and other transit hubs to reach unvaccinated children and young adults.

Canada’s 2025 outbreak similarly involved under-vaccinated pockets, including some religious communities in several provinces. When genetic sequencing showed that the same measles lineage had been circulating for at least 12 months, PAHO’s independent Regional Commission determined that endemic transmission had been reestablished, triggering the loss of national and regional elimination status.

In the United States, officials recorded more than 2,200 measles cases in 2025 and are already seeing major clusters in 2026. South Carolina has emerged as a particular hotspot, surpassing last year’s peak in Texas, according to state and federal data.

Mixed vaccine messaging in the U.S.

The policy response is unfolding against a backdrop of mixed federal messaging on vaccines. On a recent television appearance, Centers for Medicare and Medicaid Services Administrator Mehmet Oz urged Americans to get the measles shot, calling it the “clear solution” to stop the outbreaks and warning that the U.S. risks losing its measles elimination status if coverage doesn’t improve.

Health and Human Services Secretary Robert F. Kennedy Jr., a longtime critic of vaccine mandates, has emphasized individual choice. He has opposed new requirements for measles vaccination and framed immunization decisions as a matter for families, a stance that public health professionals say complicates efforts to deliver consistent messages about a disease that can be severe in young children.

A global resurgence—and a highly contagious virus

Globally, measles has been resurging as well. The World Health Organization and the U.S. Centers for Disease Control and Prevention estimate there were 10.3 million measles cases and 107,500 deaths worldwide in 2023, most among children under 5. WHO attributes the increase in large part to gaps in routine immunization during the COVID-19 pandemic and continuing service disruptions.

From a virus’s point of view, the Americas remain an attractive target. Measles is one of the most contagious human pathogens known; in an unvaccinated classroom, a single case can infect most susceptible children. The basic reproduction number — the average number of people one infected person can spread the virus to in a fully susceptible population — is typically estimated between 12 and 18.

World Cup travel adds urgency

The timing of the current resurgence, less than 18 months before the World Cup kicks off in Mexico City on June 11, 2026, adds another layer of urgency. Mexico, the United States and Canada will host matches in cities across the three countries, including Guadalajara in Jalisco, where new cases now appear daily.

In its February alert, PAHO explicitly linked measles risk to mass gatherings and high mobility events, naming the 2026 FIFA World Cup. It urged countries to increase the sensitivity of their surveillance systems through active case finding among travelers and in communities near venues, and to ensure would-be spectators are properly vaccinated before they travel.

Public health experts say the tournament could either accelerate the virus’s spread or serve as a high-profile opportunity to close immunization gaps.

“This is a setback — but it is also reversible,” PAHO Director Jarbas Barbosa said in November, when the region’s measles-free status was formally withdrawn after Canada’s outbreak. He argued that with renewed political commitment and investment in vaccination, “the Region can once again interrupt transmission.”

Reversing course will require more than emergency campaigns, health officials say. The organization is calling on countries to strengthen routine childhood immunization, expand outreach to marginalized communities, invest in laboratory capacity and maintain rapid-response teams that can move quickly when a suspected measles case is detected.

For now, on the clinic floor in Guadalajara, the work looks less like international policy than like logistics and persuasion: keeping vaccines cold in the heat, explaining side effects to anxious parents, coaxing skeptical teenagers into rolling up their sleeves.

A few blocks away, banners announcing next year’s World Cup flutter over a busy plaza. For many families there, measles is no longer a disease from history books but a present threat. Whether the virus continues to spread across the Americas — or is pushed back once again — will depend on how many of them decide to come stand in line.