At least 88 new measles cases have been reported in South Carolina, as the outbreak continues to surge, with 646 infections recorded in the state since October, officials say.

State health officials say over 500 people and students in 15 schools are in quarantine after being exposed to the virus.

The outbreak - the worst since Texas reported more than 700 measles cases in 2025 - puts the US at risk of losing its measles elimination status.

Measles is one of the world's most contagious diseases, spreading through the air via coughs and sneezes, with up to 90% of unvaccinated people nearby getting infected if exposed.

South Carolina reported 88 new measles cases since last Friday, with the outbreak centred in the northwestern town of Spartanburg, home to about 39,000 people.

The outbreak also spread to two universities in the state, Clemson and Anderson, where dozens of students are now in quarantine.

There is no specific treatment for measles, and the virus can lead to a host of complications, including pneumonia and brain swelling.

The US declared measles "eliminated" from the country in 2000, but in recent years, with a rise in anti-vaccine sentiments, the country has seen several outbreaks of the virus.

Two shots of the immunisation - proven safe - are 97% effective at preventing the virus and reduce severe infections. To achieve herd immunity - when enough of a group is immune to a disease, limiting its spread and protecting the unvaccinated - around 95% of the population must have the shots.

The measles vaccination rate for school-aged children is about 90% in Spartanburg County, the epicentre of the outbreak.

The past 12 months have marked the worst measles outbreaks in the US in decades, with over 2,000 infections. Three people died in Texas, and in recent months Utah and Arizona have also reported hundreds of measles cases.

The rise in measles cases coincides with messaging from Health Secretary Robert F Kennedy Jr that downplays both the severity of the disease and the importance of vaccination.

Kennedy, a vaccine-sceptic, has at times endorsed the MMR vaccine, while also raising unsubstantiated claims about its safety and promoting unproven alternative treatments.