The West Texas measles outbreak has ended

Summary

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. This story originally appeared at WIRED.com