The largest measles outbreak in the United States in more than 20 years has officially ended, Texas health officials announced this week.
The Texas Department of State Health Services (DSHS) declared the outbreak over on August 18, after more than 42 days passed without new cases in the counties that had seen ongoing transmission. Forty-two days is considered twice the incubation period for the virus, the threshold used to determine an outbreak’s end.
The outbreak, centered in West Texas, accounted for 762 cases in the state since it began in late January. More than two-thirds of those cases involved children, according to DSHS. A total of 99 people were hospitalized, and two children, a six-year-old and an eight-year-old, died from the disease.
Gaines County, at the heart of the outbreak, saw 414 infections, representing over half of the state’s total cases. The county’s Mennonite community and its unusually high vaccine exemption rates played a significant role in the spread.
Gaines had a 13.6% conscientious exemption rate among K-12 students in the 2023–2024 school year, more than five times higher than the state average of 2.5%.
Nationally, the Centers for Disease Control and Prevention (CDC) reported 1,356 measles cases across 40 states as of August 5, marking the highest number of cases in decades. Three deaths and 171 hospitalizations have been recorded. Health officials noted that 92% of those infected were either unvaccinated or had unknown vaccination status.
Measles, declared eliminated in the U.S. in 2000, has resurged due to declining vaccination rates. The CDC says the MMR vaccine, which protects against measles, mumps, and rubella, is 97% effective after two doses. However, herd immunity has weakened in many areas as more parents decline to vaccinate their children.
Texas DSHS Commissioner Dr. Jennifer Shuford praised the “tireless work” of public health professionals, crediting vaccination campaigns, testing, and disease monitoring with ending the outbreak. She also emphasized the need for continued vigilance, warning that additional cases are likely given ongoing outbreaks elsewhere in North America and globally.
Measles remains one of the most contagious viruses known.
According to the CDC, about 90% of unvaccinated people exposed to the virus will become infected, and one in five cases requires hospitalization. Complications can include pneumonia, brain swelling, and even death.
The last measles outbreak of similar scale in the U.S. occurred in 2019, when 1,274 cases were confirmed nationwide.