The Indiana Department of Health reported the figure in data updated Nov. 12. More than half of the people infected are under 25, and the cases are concentrated in the northeast part of the state. LaGrange County has reported 36 cases, followed by Wayne County with 21 and Adams County with 20. Allen County has confirmed 16.

Allen County Health Commissioner Dr. Thomas Gutwein said the official count likely understates the real spread. "It could go all the way to 250 or 300, and it just depends on how much the community isolates themselves if they're able or receives vaccines," he said.

The outbreak mirrors a national resurgence. The United States has recorded about 5,400 measles cases, more than double the 2025 total, according to Johns Hopkins University's measles tracker. The surge comes more than two decades after the virus was declared eliminated in the country.

Measles typically begins with a high fever and runny nose before a rash of small raised bumps appears near the hairline and spreads down the body, according to the Centers for Disease Control and Prevention. The virus can cause lasting harm, including seizures, brain and lung damage, pneumonia and a loss of immunity to other infections. Unvaccinated people who are exposed are advised to quarantine for 21 days.

Most of Indiana's cases involve unvaccinated people. The measles, mumps and rubella vaccine is given in two doses, with the first usually administered at about 12 months of age. Sara Dillard, communications director for the Indiana Immunization Coalition, said roughly 95% of a population must be vaccinated to achieve community immunity.

"Speaking specifically to Indiana in the 2025 to 2026 school year, we only had 91% coverage among kindergartners," Dillard said. "So that's what makes this outbreak so dangerous because we have children who are left vulnerable."

Dillard noted that some people cannot be vaccinated because they are too young or have health conditions, which makes protecting them dependent on the immunity of those around them. "It's not just about vaccinating yourself, your family. You know, do it for your neighbor," she said.

Gutwein urged anyone who is not vaccinated to consult a health provider and get the MMR shots if they are able. One dose provides about 93% immunity, and two doses raise that to about 97%. "Just get a vaccine. That's the best thing you can do," he said. "It'll be effective even within three days of being exposed. You can still get a vaccine that'll protect you."

Vaccines are available through county health departments, hospitals and health clinics, and the Indiana Immunization Clinic operates mobile clinics around the state.