More than 150 unvaccinated schoolchildren have been quarantined for 21 days in South Carolina after being exposed to measles, as the United States faces its worst outbreak of the disease in over three decades.
Health officials say the quarantined students, who did not receive the required measles, mumps and rubella (MMR) vaccine, will remain at home for the full incubation period to prevent further spread.
The children attend Global Academy of South Carolina and Fairforest Elementary in Spartanburg County. The South Carolina Department of Public Health confirmed its eighth measles case in two weeks on Thursday, this time in neighboring Greenville County.
“What this case tells us is that there is active, unrecognized community transmission of measles occurring in the Upstate, which makes it vital to ensure that the public have received their measles vaccinations,” the department said in a statement.
The US Centers for Disease Control and Prevention (CDC) reports 1,563 confirmed cases nationwide so far in 2025, the highest level in 33 years. Recent surges have been recorded in New Mexico, Texas, Utah, and Arizona, where dozens have fallen ill.
Earlier this year, outbreaks in west Texas and New Mexico killed three people, the first measles-related deaths in the US since 2015. Most infections have been among unvaccinated individuals, according to the CDC.
Globally, health authorities warn of a wider crisis. UNICEF says measles cases have surged in over 100 countries in the past five years. In Canada, more than 5,000 cases have been recorded this year, triple the number in the US, with the majority reported in Alberta and Ontario.
The MMR vaccine, which is 97% effective, remains the best protection against the highly contagious disease, which can cause pneumonia, brain swelling, and death.