PAHO intensifies call to strengthen vaccination in light of rising measles cases in the Americas

Washington, D.C., 19 September 2025 (PAHO) - The Pan American Health Organization (PAHO) is urging countries in the Americas to strengthen vaccination efforts, improve surveillance, and accelerate outbreak response following a rise in measles cases in the region. As of September 12, 2025, 11,313 cases and 23 deaths have been confirmed in ten countries-a 31-fold increase compared to the 358 cases reported in the same period in 2024, according to PAHO's latest epidemiological update published today.

"Measles is a preventable disease thanks to vaccination, but low coverage in vulnerable communities is fueling these outbreaks," said Dr Daniel Salas, Executive Manager of PAHO's Special Programme on Comprehensive Immunization. "Strengthening immunization-knowing that the measles vaccine is safe and highly effective-is essential to protect millions across the Americas," he added.

Ten countries have reported cases this year, with Canada (4,849 cases, 1 death), Mexico (4,553 cases, 19 deaths), and the United States (1,454 cases, 3 deaths) accounting for 96% of total cases in the Region. Additional cases have been reported in Bolivia (320), Brazil (28), Argentina (35), Belize (34), Paraguay (35), Peru (4), and Costa Rica (1).

The outbreaks have primarily affected communities with low vaccination coverage or resistance to vaccination. The most affected group was children under 1 year of age (6.6 cases per 100,000 population), followed by children aged 1 to 4 years (3.6 per 100,000). Over 71% of confirmed cases were unvaccinated, while vaccination status was unknown in an additional 18%.

Data indicates regional transmission initially driven by imported cases, with 71% classified as importation-related and 16% as imported cases. This highlights the urgent need to bolster both epidemiological surveillance and vaccination coverage.

In 2024, the Region observed a slight increase in measles vaccination coverage, reaching 89% for the first dose (MMR1), up from 87% in 2023, and 79% for the second dose (MMR2), compared to 76% the previous year. However, only 31% of countries and territories achieved MMR1 coverage equal to or above 95%, and just 20% reached that threshold for the second dose. Moreover, 49% of countries reported MMR2 coverage below 80%, underscoring persistent immunization gaps.

Vaccine hesitancy and limited access in vulnerable rural and urban communities remain significant barriers. To effectively prevent measles outbreaks, population-level coverage of at least 95% with both doses is required.

At the global level, the World Health Organization (WHO) has reported 164,582 confirmed measles cases in 173 countries as of 9 September 2025, based on a total of 360,321 suspected cases. The most affected regions are the Eastern Mediterranean (34%), Africa (23%), and Europe (18%).

PAHO recommendations

To stop transmission, PAHO urges countries to:

• Achieve vaccination coverage of at least 95% with two doses of measles-containing vaccine in every municipality.
• Immediately vaccinate all contacts of confirmed or suspected cases up to 39 years of age, ideally within the first 72 hours.
• Intensify vaccination campaigns in areas with outbreaks or at risk of spread, and administer vitamin A to confirmed cases to reduce the risk of complications.
• Strengthen surveillance in high-risk, border, and silent transmission areas, including active case finding.
• Implement rapid response plans, including trained teams, situation rooms, and adequate hospital isolation protocols.
• Vaccinate international travelers without documented measles immunization, including children aged 6 to 11 months as an exceptional measure, at least 10 days before traveling to areas with active transmission.

PAHO also emphasizes training health personnel and engaging communities to combat misinformation, using tools such as online courses available through the PAHO Virtual Campus for Public Health.