A large measles outbreak in Texas that has affected 762 people has now ended, according to an announcement Monday by the Texas Department of State Health Services. The agency says it has been more than 42 days since a new case was reported in any of the counties that previously showed evidence of ongoing transmission.

The outbreak has contributed to the worst year for measles cases in the United States in more than 30 years. As of August 5, the most recent update from the Centers for Disease Control and Prevention, a total of 1,356 confirmed measles cases have been reported across the country this year. For comparison, there were just 285 measles cases in 2024.

The Texas outbreak began in January in a rural Mennonite community with low vaccination rates. More than two-thirds of the state’s reported cases were in children, and two children in Texas died of the virus. Both were unvaccinated and had no known underlying conditions. Over the course of the outbreak, a total of 99 people were hospitalized, representing 13 percent of cases.

Measles is a highly contagious respiratory illness that can temporarily weaken the immune system, leaving individuals vulnerable to secondary infections such as pneumonia. In rare cases, it can also lead to swelling of the brain and long-term neurological damage. It can also cause pregnancy complications, such as premature birth and babies with low birth weight. The best way to prevent the disease is the measles, mumps, and rubella (MMR) vaccine. One dose of the vaccine is 93 percent effective against measles while two doses is 97 percent effective.

A measles outbreak is considered over after 42 days if no new cases are discovered because it is double the disease’s maximum incubation period—the longest time it can take between when a person is exposed to the virus and when they develop symptoms.

The CDC defines an outbreak as three or more related cases. The West Texas outbreak has been linked to cases in neighboring states, Mexico, and Canada.

While the Texas outbreak has ended, measles cases are still being reported elsewhere in the country. According to the CDC, 40 other states have reported cases, and a total of 32 US outbreaks have been reported in 2025, compared with 16 outbreaks in 2024.

The ongoing outbreaks put the country’s measles elimination status at risk. The designation means there is no ongoing domestic spread of measles for longer than 12 months. The US achieved that status in 2000 after years of increasing vaccination rates but almost lost it in 2019, when measles cases swept through undervaccinated Orthodox Jewish communities in New York for much of the year.

As vaccination rates continue to decline in the US, public health researchers warn that outbreaks of measles and other diseases are likely. One recent peer-reviewed paper found that at current state-level vaccination rates, measles could reestablish itself and become endemic again within the next two decades.