PAHO issues epidemiological alert!

THE PAN AMERICAN HEALTH ORGANIZATION (PAHO) has issued a new epidemiological alert on measles for the Region of the Americas, calling on countries to intensify epidemiological surveillance, vaccination, and rapid outbreak response activities to interrupt transmission and protect vulnerable populations.

Published on February 3,2026 the alert highlights the ongoing occurrence of cases and outbreaks in several countries in the Region, against a backdrop of a sustained increase of measles cases in 2025 compared with the previous five years, a trend that appears to be continuing into 2026.

PAHO recommends strengthening surveillance and active case finding, including laboratory diagnosis; implementing supplementary immunization activities to close immunity gaps; and ensuring a timely response to any suspected measles case.

Epidemiological situation in the Region In 2025, the Region reported 14,891 confirmed measles cases, including 29 deaths, across 13 countries: Argentina (36 cases), Belize (44 cases), Bolivia (597 cases), Brazil (38 cases), Canada (5,436 cases, including 2 deaths), Costa Rica (1 case), El Salvador (1 case), the United States (2,242 cases, including 3 deaths), Guatemala (1 case), Mexico (6,428 cases, including 24 deaths), Paraguay (49 cases), Peru (5 cases), and Uruguay (13 cases). This represents a 32-fold increase compared with the 466 cases reported in 2024.

During the first three weeks of 2026, an additional 1,031 measles cases were confirmed in seven countries— Bolivia (10), Canada (67), Chile (1), the United States (171), Guatemala (41), Mexico (740), and Uruguay (1)—with no deaths reported. This represents a 43-fold increase compared with the 23 cases reported during the same period in 2025.

Available evidence indicates that, among confirmed cases with vaccination information, 78% were unvaccinated and 11% had an unknown vaccination status. While the largest proportion of cases occurred among adolescents and young adults, the highest incidence rates were observed in infants under one year of age, followed by children aged 1–4 years and 5–9 years. This underscores the need to complete vaccination schedules and employ additional protective measures in outbreak settings.

Globally, the World Health Organization (WHO) reported that during 2025, more than 552,000 suspected measles cases were notified across 179 countries, of which nearly 45% (247,623) were confirmed, reflecting a global resurgence of the disease amid persistent immunization gaps.

Vaccination coverage and immunity gaps Regional vaccination coverage with the measles, rubella, and mumps (MMR) vaccine in the Americas showed a slight increase in 2024 compared with 2023 (from 87% to 89% for the first dose, and from 76% to 79% for the second dose), but remains below the 95% coverage needed to prevent outbreaks. Only 33% of countries and territories in the Region achieved at least 95% coverage with the first dose, and just 20% reached that target for the second dose. An estimated 1.5 million children did not receive any dose of the vaccine in 2024.

PAHO has emphasized that measles is highly contagious but preventable through timely vaccination with two doses of the MMR vaccine. In countries experiencing active outbreaks, PAHO reiterated the need to intensify vaccination, active case finding, and rapid response to interrupt transmission.

At the same time, for all countries in the Region, PAHO has stressed the importance of closing vaccination coverage gaps, maintaining sensitive and timely surveillance, and protecting travellers through vaccination, particularly those travelling to areas with active transmission.

In the context of the 2026 FIFA World Cup and other mass gatherings involving high population mobility, PAHO recommends that countries increase the sensitivity of their surveillance systems through the implementation of active case finding to promptly detect the presence or absence of measles and rubella cases.

PAHO commits to continue to monitor the measles situation and update its recommendations as the epidemiological situation evolves.