More than 200 people are being quarantined in the south after an outbreak of measles continues to spread among partially vaccinated and unvaccinated Americans.
The outbreak in South Carolina, described as ‘accelerating’ in the wake of Thanksgiving travel and low vaccination rates, has reached 111 cases in the state’s northwest region, known as the Upstate region, with cases traced to a church in the area, officials said.
Of those 111 people, 105 were unvaccinated and three were partially vaccinated, state epidemiologist Linda Bell said at a news briefing.
Bell said 27 new cases had been reported since Friday. According to the CDC, South Carolina has reported 123 cases in 2025. There was one case in 2024.
Now, 254 people who could have been exposed have been placed in quarantine as a precaution as of Tuesday, 16 of which are in isolation, the state’s Department of Public Health (DPH) reported.
The measles, mumps and rubella (MMR) vaccine is typically given in two doses to children between ages 12 and 15 months and again between ages four and six. It is not known the ages of the measles patients or people quarantined.
The vaccine is 97 percent effective in preventing infection for those who receive both doses, according to the CDC. One dose is 93 percent effective.
A vaccination rate of 95 percent is needed to achieve herd immunity. But nationwide, only 92.5 percent of kindergarteners have gotten both doses of the shot, posing a threat to herd immunity.
In South Carolina, just 91 percent of kindergarteners have been vaccinated against measles. And one in 20 in the state are exempt from one or more vaccines due to medical or religious reasons.
Measles is considered the world’s most infectious disease because people who are not vaccinated have a 90 percent chance of getting sick if they are exposed, even from sharing the same air, briefly or hours later, with someone who has measles.
Three in 1,000 people who contract measles will die.
Bell said: ‘Accelerating is an accurate term. That is a spike in cases we are concerned about,’ adding that the state has a ‘lower than hoped for’ vaccination rate.
Measles, which was once considered eliminated in the US, has now infected 1,912 Americans and killed three people this year.
It’s the largest outbreak since 2,126 cases were reported in 1992.
Five hundred of these cases are in Americans under 5 years old; 786 are in 5- to 19-year-olds; 613 are among Americans 20 and older; and 13 cases are in people of unknown age.
According to the CDC, 92 percent are unvaccinated or have an unknown vaccine status. Three percent have received one dose of the MMR vaccine and four percent have received both doses.
Of those sickened in the US, 218, 11 percent, are hospitalized, with the majority of those, 21 percent, being children under 5.
In a statement Bell made in October, she said: ‘We actually anticipate that more cases may occur. The measles virus won’t be contained within schools, within school districts or by county lines, but the MMR vaccine, by providing lifelong immunity to the majority of those vaccinated, will contain the virus.
‘And for this reason, we’re urging those who are not vaccinated to consider getting that protection now.’
Measles is an infectious, but preventable, disease caused by a virus that leads to flu-like symptoms, a rash that starts on the face and spreads down the body, and, in severe cases, pneumonia, seizures, brain inflammation, permanent brain damage, and death.
The virus is spread through direct contact with infectious droplets or through the air.
Patients with a measles infection are contagious from four days before the rash through four days after the rash appears.
Deaths typically occur from acute encephalitis, or brain swelling, when the virus travels to the central nervous system, or pneumonia if it migrates to the lungs.
Before the current two-dose childhood vaccine’s approval in 1968, there were up to 500 US deaths each year from measles, 48,000 hospitalizations and 1,000 cases of brain swelling.
Roughly three million to four million people were infected every year.
