US Measles Cases Surge Past 1,000 in Largest Outbreak Since 2019

Federal health officials have confirmed that measles cases in the United States have surpassed 1,000 in 2025, marking the second-worst outbreak since the disease was declared eliminated in 2000. The rapidly spreading virus, which has claimed the lives of two unvaccinated children in Texas, has now been detected in 31 states with public health experts warning that declining vaccination rates are fueling the resurgence.

The Centers for Disease Control and Prevention (CDC) reported Friday that 93% of this year’s cases are associated with 14 distinct outbreaks, with the majority concentrated in West Texas, according to CDC’s measles tracking data.

Texas Epicenter Accounts for Over 700 Cases

The outbreak’s epicenter remains in West Texas, where 709 cases have been confirmed since late January, primarily affecting the South Plains and Panhandle regions. This represents more than two-thirds of all national cases. Officials have confirmed that 92 patients in Texas required hospitalization, and two unvaccinated school-aged children with no known underlying conditions have died from complications of the disease.

“Less than one percent, or fewer than 10 of the confirmed cases, are estimated to be actively infectious,” the Texas Department of State Health Services stated in its May 9 update. However, health officials anticipate additional cases as the outbreak continues to expand in surrounding areas and communities with low vaccination rates.

The outbreak has already spread beyond Texas borders, with linked cases identified in neighboring states including New Mexico, Oklahoma, and Kansas, as reported by NBC News.

Declining Vaccination Rates Fuel Resurgence

Health experts point to falling immunization coverage as the primary driver behind the outbreaks. CDC data reveals that measles vaccination rates among kindergarteners have dropped from 95.2% in the 2019-2020 school year to just 92.7% in 2023-2024, falling below the critical 95% threshold needed for community immunity.

The overwhelming majority of cases have occurred in unvaccinated individuals. According to CDC analysis, approximately 96% of confirmed cases nationwide involved people who were either unvaccinated or had unknown vaccination status. In Texas specifically, 99% of cases were in individuals without documented vaccination.

“When more than 95% of people in a community are vaccinated, most people are protected through community immunity,” the CDC emphasized in recent guidance. This protection is particularly crucial for infants under 12 months who are too young to receive the vaccine, as well as immunocompromised individuals who cannot be vaccinated.

Unprecedented Sequence of Outbreaks

The 2025 outbreak follows concerning trends from 2024, when 16 separate outbreaks were reported across the country—a significant increase from just four outbreaks in 2023. The current situation represents the most severe measles resurgence since 2019, when 1,274 cases were confirmed nationwide.

The World Health Organization (WHO) has issued alerts about the global implications of the U.S. outbreak, noting that measles cases linked to the Texas outbreak have been detected in Mexico. WHO officials emphasized that the growing U.S. outbreaks, combined with similar surges throughout the Americas, threaten decades of progress toward regional elimination of the disease.

“As of 18 April 2025, a total of 2,318 measles cases, including three deaths, have been confirmed in six countries in the WHO Region of the Americas, an 11-fold increase compared to the same period in 2024,” according to the organization’s recent epidemiological update.

Targeted Response Efforts Underway

Federal and state health agencies have mobilized significant resources to contain the outbreak. The CDC activated a Level 3 Incident Management Structure in March to provide technical assistance with diagnostics, case investigation, and post-exposure prophylaxis in affected communities.

In Texas, health officials have expanded vaccination recommendations beyond standard guidelines for affected counties. These include administering an early dose of the measles, mumps and rubella (MMR) vaccine to infants as young as 6 months in outbreak areas, as well as offering second doses to adults who previously received only one dose.

“The best way to prevent getting sick is to be immunized with two doses of a vaccine against measles,” the Texas Department of State Health Services emphasized in its latest guidance, noting that the MMR vaccine is highly effective at preventing infection when properly administered.

Travel Concerns As Summer Season Approaches

With the summer travel season approaching, health officials are particularly concerned about potential interstate and international spread from current hotspots. The CDC has issued travel advisories urging individuals, especially those planning international travel, to ensure they are fully vaccinated regardless of destination.

Measles is one of the world’s most contagious viruses, with each infected person capable of spreading the disease to 12-18 others in unvaccinated populations. The virus can remain infectious in the air for up to two hours after an infected person has left an area, making crowded travel hubs potential transmission points.

“The risk for widespread measles in the United States remains low due to robust U.S. immunization and surveillance programs,” the CDC noted in its recent Health Alert Network advisory, while emphasizing the critical need for continued vigilance and vaccination efforts.