The measles outbreak that started in Texas in late January continues to grow. As of March 18, 2025, confirmed cases in the outbreak, which now spans Texas, New Mexico and Oklahoma, reached 321, surpassing the number of confirmed cases recorded for all of the U.S. in 2024. 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.