Mexico Measles Outbreak: Risk of Losing Status & PAHO Alert

The Americas are facing a resurgence of measles, prompting heightened concern from public health officials. Following a period where the region had successfully eliminated endemic measles transmission, outbreaks in the United States and Mexico are threatening to reverse that progress. The Pan American Health Organization (PAHO) is calling for renewed regional action to address the growing challenge.

The region had regained measles elimination status in 2024, a significant achievement built on coordinated vaccination efforts, robust surveillance systems and effective outbreak response strategies. However, outbreaks beginning in the United States on January 20, 2025, and in Mexico on February 1, 2025, have jeopardized this status. To maintain elimination, a country must demonstrate the interruption of endemic measles transmission for at least 12 consecutive months, supported by comprehensive data.

PAHO’s Regional Monitoring and Re-Verification Commission for Measles, Rubella, and Congenital Rubella Syndrome (RVC) is actively monitoring the situation. The commission has scheduled a virtual meeting with representatives from the United States and Mexico on April 13, 2026, to review their measles elimination status. This meeting will involve a thorough examination of national reports, epidemiological data, laboratory evidence, and findings from field investigations.

The RVC operates as an independent technical body reporting directly to the PAHO Director. Its mandate is to verify the elimination of measles, rubella, and congenital rubella syndrome across PAHO Member States and to assess the reestablishment of endemic transmission. Endemic transmission is defined as a continuous chain of measles virus transmission of the same genotype and lineage lasting 12 months or more within a defined geographical area.

Mexico is currently experiencing a particularly significant outbreak. As of February 5, 2026, the country leads the Americas with nearly 2,000 confirmed measles cases and over 5,200 suspected cases. This outbreak is largely attributed to vaccine hesitancy, particularly within certain communities. In Jalisco, a key host city for the upcoming 2026 FIFA World Cup, authorities have mandated the use of face masks in schools as a precautionary measure. The state has confirmed 1,163 cases and suspects another 2,092 as of the same date.

The outbreak in Mexico initially emerged in the northern state of Chihuahua last year, stemming from a case involving a child from a Mennonite community who had traveled to a region of Texas experiencing an outbreak. Cases subsequently spread within Mennonite communities, which have lower vaccination rates, and then expanded across the country.

In February 2025, Mexico reported the start of its ongoing measles outbreak, with over 4,000 confirmed cases reported by that date. This contributed to PAHO’s announcement in November 2025 that the Americas had lost its region-wide measles elimination status.

The situation is prompting a broader epidemiological alert from PAHO, urging strengthened vaccination and surveillance efforts throughout the Americas. The organization emphasizes the importance of maintaining high vaccination coverage to prevent further spread and protect vulnerable populations. The outbreaks underscore the critical role of vaccination in controlling this highly contagious disease.

The RVC’s review process will culminate in recommendations submitted to the PAHO Director, who will then formally determine each country’s classification and communicate the decision to national authorities. The outcome of these assessments will be crucial in guiding regional strategies to regain and sustain measles elimination in the Americas.

The current outbreaks serve as a stark reminder of the ongoing threat posed by measles and the importance of sustained public health vigilance. Maintaining high vaccination rates remains the most effective strategy for preventing outbreaks and protecting communities from this preventable disease.