Officials in the United States have announced that the measles outbreak in the southern state of South Carolina has grown to 185 cases, up nine from earlier this week.

In Friday’s update, state officials specified that 172 of the cases involved patients who had not received the measles, mumps and rubella (MMR) vaccine, designed to protect against infection.

Recommended Stories

list of 3 items

• list 1 of 3WHO warns $1.7bn funding shortfall threatens polio eradication efforts
• list 2 of 3Why has Canada lost its measles-free status – and could the US be next?
• list 3 of 3Sudan’s Darfur grapples with severe measles outbreak amid ongoing violence

end of list

Four others involved patients who were partially vaccinated, four had an unknown vaccination status, and another four cases are still under investigation. Only one of the infections involved a fully vaccinated person.

Measles, a highly infectious and sometimes deadly virus, was declared eliminated in the US more than 25 years ago. But the past year has presented increasing challenges to maintaining that status.

Diseases are generally declared eliminated when there is no local transmission in a given region, although cases can still be “imported” from abroad.

The US’s elimination status is largely credited to the success of the MMR vaccine.

In 1963, the first measles vaccine was licensed in the US, and by 1971, the combination MMR vaccine was unveiled to protect against the three illnesses at once. Two shots are typically recommended to achieve full vaccination status.

Initially, in 1978, the US Centers for Disease Control and Prevention (CDC) set 1982 as a deadline to achieve the elimination of measles in the country. It missed that target by nearly 18 years, reaching elimination status in 2000.

But vaccine hesitancy has been blamed for allowing the virus to spread in the US, both then and now.

While the death rate for measles is relatively low, its infection rate is high. The CDC estimates that, if one person has the virus, they could infect nine out of every 10 people around them.

The World Health Organization says that, for every 1,000 reported cases, there are about two to three deaths.

Children are especially vulnerable. Complications can include high fever, hearing or vision loss and encephalitis, an inflammation of the brain.

Typically, medical professionals recommend children be vaccinated early in their lives, receiving their first dose before 15 months of age and their second by age six. The vaccine is widely accepted as safe.

But vaccine scepticism has been on the rise in the US, with critics blaming, in part, policies implemented under the administration of President Donald Trump.

According to CDC data, the MMR vaccination rate in the US was 95.2 percent among kindergarteners during the 2019-2020 school year.

That number, however, tumbled to 92.7 percent by the 2023-2024 school year, representing a difference of 280,000 kindergarteners.

2025 represented a high-water mark in the resurgence of the measles virus. The CDC reported 2,065 cases of measles last year, the most since 1991 — and more than seven times the rate of 2024, when only 285 cases were reported.

One of the biggest outbreaks took place in Texas, where three people died from the virus, with the first reported last February. Prior to that incident, no death had been reported from measles in the US since 2015.

In the wake of that death, Trump’s Health and Human Services Secretary Robert F Kennedy Jr encouraged vaccination, writing on social media, “The most effective way to prevent the spread of measles is the MMR vaccine.”

But Kennedy, who is not a medical professional, has since expressed views that appeared to discourage the vaccine’s use.

In late April, for instance, he told NewsNation, “The MMR vaccine contains a lot of aborted fetus debris and DNA particles.”

Experts, however, have denounced that claim as false. While the rubella part of the vaccine was developed using a cell culture that came from an elective abortion in the 1960s, no fetal tissue has been used since, nor is there any fetal issue in the vaccine.

Kennedy has also spread unfounded claims that purport to link vaccination to autism, despite widespread outcry from the medical community.

In South Carolina, the current measles outbreak is concentrated in the northwest. The South Carolina Department of Public Health says that the reported infections are largely in children under the age of 17.

One Democratic candidate running in the state’s 2026 midterm elections, paediatrician Annie Andrews, has made combating the outbreak a central part of her campaign. She hopes to unseat incumbent Senator Lindsey Graham, a Republican, in November’s vote.

“If you told me back in medical school that someday I would be running for the Senate and my campaign slogan would be ‘It’s me or the measles’ I WOULD DEFINITELY NOT HAVE BELIEVED YOU,” she wrote on social media on Friday.