The measles outbreak that started in Texas in late January continues to grow. As of March 27, 2025, confirmed cases across the United States reached 483, surpassing the total number of confirmed cases recorded in 2024. About 93 percent of the cases are associated with the outbreak, which now spans Texas, New Mexico and Oklahoma.
The vast majority of cases are in people who are not vaccinated. Meanwhile, a lack of clarity from health authorities is leaving people with questions about whether they need to get revaccinated.
In a Q&A with The Conversation U.S., Daniel Pastula, a neurologist and medical epidemiologist from the University of Colorado Anschutz Medical Campus and Colorado School of Public Health, explained how and when you should take action.
Should adults get another shot of the measles vaccine?
The measles vaccine, which first became available in the U.S. in 1963, contains a live but significantly weakened strain of the measles virus. This modified strain is too weak to cause measles, but it is similar enough to the wild type measles virus to train the immune system to recognize it. Most people who have received the live measles vaccine won’t need an additional shot now, but here is what you need to know:…