U.S. Faces Largest Measles Outbreak in Three Decades Due to Falling Vaccination Rates

The United States is confronting its most severe measles outbreak in over three decades, with 1,514 confirmed cases reported across 42 jurisdictions as of October 2, 2025. This resurgence is primarily attributed to declining vaccination rates, particularly among children, and is further exacerbated by vaccine misinformation and policy changes. The outbreak has resulted in three deaths and numerous hospitalizations, underscoring the critical need for renewed public health efforts to bolster immunization coverage and combat misinformation.

The outbreak began in January 2025, predominantly affecting unvaccinated individuals in close-knit communities in Texas, New Mexico, and Oklahoma. By April 17, 2025, the Centers for Disease Control and Prevention (CDC) reported 800 cases across 25 jurisdictions, with Texas accounting for 597 cases. By July 8, 2025, the CDC confirmed 1,288 cases across 39 states, marking the highest level in 33 years. In August 2025, the Pan American Health Organization (PAHO) reported that the United States had 1,356 confirmed cases, contributing to a regional total of 10,139 cases across ten countries in the Americas. In September 2025, Texas officials declared an end to the state's outbreak, which had resulted in 762 infections and two deaths.

The outbreak has disproportionately affected unvaccinated individuals. Children under five years old represent 30% of cases, those aged 5–19 years account for 38%, and adults over 20 years make up 32%. Approximately 13% of cases have required hospitalization, with the highest rate (23%) among children under five. Three deaths have been confirmed, all involving unvaccinated individuals, including two children in Texas and one adult in New Mexico.

The resurgence of measles is closely linked to declining vaccination rates. The national MMR (measles, mumps, and rubella) vaccination rate among kindergartners has decreased to 92.7%, below the 95% threshold required for herd immunity. Misinformation about vaccine safety, including debunked claims linking the MMR vaccine to autism, has contributed to hesitancy. Social media platforms have amplified these misconceptions, leading to decreased vaccination rates in certain communities. The outbreak has been particularly severe in close-knit communities with low vaccination coverage, such as Mennonite groups in Texas, New Mexico, and Oklahoma.

Health authorities have implemented several measures to control the outbreak. Targeted immunization efforts have been conducted in affected areas to increase coverage. Initiatives to counter misinformation and promote the safety and efficacy of the MMR vaccine have been intensified. Some states have reconsidered non-medical exemptions for vaccinations to bolster immunization rates.

The outbreak has highlighted several critical issues. The need for robust disease surveillance and rapid response capabilities has been underscored. The role of misinformation in undermining public health efforts has been brought to the forefront, emphasizing the need for effective communication strategies. Building trust within communities resistant to vaccination is essential for preventing future outbreaks.

This outbreak is the most significant since measles was declared eliminated in the United States in 2000. The current situation serves as a stark reminder of the importance of maintaining high vaccination coverage to prevent the re-emergence of preventable diseases.

Health officials emphasize the importance of the measles, mumps, and rubella (MMR) vaccine, which is 97% effective after two doses, and are urging increased vaccination efforts to control the spread.