Mounting measles cases drive concerns in schools as hundreds quarantine

South Carolina's measles outbreak has grown to 15 cases, state health officials reported Friday, a small increase from a few days ago.

The new cases are among those who'd been exposed to the virus at school, but developed symptoms in quarantine. It's not known if they're adults or children, but 139 students are still currently in quarantine in the state.

"We are fortunate that those we have identified as being exposed to measles are complying with our guidance to quarantine for the period that they could not expose others," Dr. Linda Bell, epidemiologist for South Carolina, said in a statement to NBC News.

Those who aren't vaccinated against measles are recommended to stay home, away from others for a 21-day quarantine. That's how long it can take to develop measles symptoms -- high fever, red eyes and a rash -- after being exposed.

"We recognize that quarantining is challenging for families and communities, and we continue to strongly encourage getting vaccinated, which would make quarantining unnecessary due to the MMR vaccine's proven effectiveness for decades," Bell said, referring to the measles-mumps-rubella shot.

As measles keeps popping up in some pockets of the United States, the possibility of being exposed to the highly contagious virus continues. At least 1,596 measles cases have been confirmed in 2025, according to data from the Centers for Disease Control and Prevention, but it's unclear how many people have been asked to quarantine.

In Ohio, where five cases in the central part of the state have been reported within the last 2½ weeks, quarantine for 122 people was expected to end Friday. A 1-year-old had to be hospitalized for several days after developing pneumonia.

The quarantine disruptions are prompting some pushback in the affected communities.

"For many in our community, they're frustrated, like, 'Why don't you just get your kid vaccinated?'" Dr. Mysheika Roberts, health commissioner for Columbus, Ohio, said in an interview. Measles exposures, including one at an early childhood learning center late last month, triggered the 21-day quarantine, she said.

"When you make a decision not to vaccinate your child or to delay the vaccination, you're not just impacting your child and your household. You can be impacting that entire community," Roberts said. "It's a ripple effect that I don't think the average individual who makes this decision understands."

In the Minneapolis-St. Paul area, 118 kids are now back in school after they were exposed to an outbreak of 20 measles cases. Their quarantine ended Wednesday, according to a spokesman for the Minnesota Health Department.

Still, public health officials are bracing for future outbreaks.

"We actually anticipate that more cases may occur," Bell said during a media briefing Thursday. "The measles virus won't be contained within schools, within school districts or by county lines."

"My concern is that this is going to keep happening, that this is going to be our new normal," Roberts said.

Children who have been given the MMR vaccine don't have to quarantine if exposed. Two doses, given around age 1 and again around age 5, are 97% effective in preventing measles infections, according to the CDC.

'Why don't you just get your kid vaccinated?' Public frustration grows amid measles outbreaks