One charter school in South Carolina’s Upstate region had an immunization rate at just 17%, according to state health data.

A South Carolina measles outbreak has grown to 16 people, including five new cases from schools with low vaccination rates, state health officials said Oct. 14.

The South Carolina Department of Health first identified the outbreak of the highly contagious viral disease in the state’s Upstate region in early October. A dozen cases have been concentrated in Spartanburg County, where two elementary schools have nearly 140 students quarantining at home because they weren’t vaccinated against measles.

Some cases have been related to travel or through close contacts of known cases. Others have no known source, which state health officials said suggests “measles is circulating in the community and could spread further.” 

Five new cases announced Oct. 14 are from students exposed in school settings and were quarantining at home, according to a public health department news release. Exposures have occurred at two Spartanburg County schools, Global Academy of South Carolina and Fairforest Elementary School, which both have low vaccination rates.

Just 17% of students at Global Academy, a K-5th-grade charter school of more than 600 students, had their required immunizations, according to a state report from the 2024-25 academic school year, as the Post and Courier reported. The figure is far below the 95% threshold needed to prevent outbreaks in communities.

Fairforest Elementary, a public school, had immunization rates at 85% among more than 760 students.

Declining vaccination rates causing increased outbreaks

The United States has seen record levels of measles cases in 2025, with over 1,500 people infected, mostly connected to a large outbreak in West Texas among unvaccinated people. Three people died in the Texas outbreak, including the first measles death of an unvaccinated child in a decade. The Centers for Disease Control and Prevention declared the Texas outbreak over in August.

There have been 44 outbreaks so far in 2025. Around 87% of confirmed cases are related to outbreaks.

The country had eliminated measles in 2000, meaning there was no spread and new cases only came from abroad. But declining vaccination rates — often from parents exempting their children from receiving school-mandated vaccines — have allowed the disease to return in force.

Measles spreads when an infected person coughs or sneezes. People can be infected by breathing contaminated air, where the virus can remain for up to two hours, or by touching their mouth, eyes, or nose after touching a contaminated surface.

Symptoms typically appear a week or two after exposure and include high fever, cough, runny nose, and watery eyes, according to the CDC. A measles rash, the telltale sign of infection, appears three to five days after the onset of the first symptoms.

Vaccines are highly effective at preventing infection. The full two-dose measles, mumps and rubella vaccine provides 97% protection against the virus, and it’s first administered around the child’s first first birthday and again at 4 to 6 years old.

About 1 in 5 people who get measles will be hospitalized, according to the CDC. One in 20 children infected with measles end up with pneumonia, which is the most common cause of death in children. About 1 in 1,000 children who get sick develop encephalitis, or brain inflammation, which can lead to deafness, convulsions or intellectual disabilities.

Death from respiratory or neurologic complications happens in about 1-3 in 1,000 children who get sick.

In South Carolina, officials plan to offer free vaccinations. The number of cases suggests “unrecognized community transmission,” the state health department said, which doesn’t respect county lines or school zones.

Contributing: Thao Nguyen and Mary Walrath-Holdridge of USA TODAY