Measles outbreak surges in southern US, forcing quarantines as even fully vaccinated people get disease

More than 100 people in South Carolina have been struck by highly contagious measles in the past week, health officials have warned.

The South Carolina Department of Public Health (DPH) said Tuesday the state has seen 124 measles cases since Friday, bringing its total to 434 since September 2025. 

The outbreak has forced 409 residents into quarantine and another 17 into isolation. The latest round of quarantines will end for these residents on February 6. 

Health officials also noted one person was confirmed to have attended the South Carolina State Museum in Columbia while infectious on January 2 between the hours of 1pm and 5pm, leaving anyone at the museum during that time potentially exposed. 

The person did not know they were infectious at the time. No further details about the individual were revealed. 

DPH said in a statement: ‘DPH is asking anyone who was at the museum during that specific day and time to contact a health care provider if you believe you may have been exposed and you develop symptoms, or if you do not have immunity to measles. 

‘People who were exposed, especially those without immunity through vaccination or previous disease, should monitor for symptoms through Jan. 23.’

Among those infected, six people had received both doses of their measles, mumps and rubella (MMR) vaccine, leaving them with just a three percent chance of becoming infected. 

The vast majority of measles cases are seen in those who are not vaccinated.  

Of the 434 cases since September 2025, 105 were under five years old, 287 were between ages five and 17, 36 were over 18 and six were minors under 18 whose exact ages were not disclosed. 

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.

DPH urged those who may have been exposed to watch for symptoms for 21 days. 

According to the CDC, 93 percent of measles cases are in unvaccinated people or those with an unknown vaccine status. Three percent have received one dose of the MMR vaccine and four percent have received both doses. 

The measles, mumps and rubella (MMR) vaccine is typically given once between ages 12 and 15 months and again between ages four and six.

The vast majority of infected people in South Carolina, 378, were unvaccinated. Three were partially vaccinated, 47 were unknown and six were fully vaccinated.   

The odds of a vaccinated person becoming infected is very low, about three percent. Even if infection occurs, symptoms are typically far milder and the risk of severe complications or transmission is drastically reduced.

According to national data, 11 percent, or 240 people infected, have been hospitalized and three people have died in the current outbreak. 

Nearly 20 percent of children under five infected during the current outbreak have required hospitalization.

The US formally eliminated measles in 2000, meaning there had been no community spread in 12 months, thanks to widespread uptake of the measles, mumps and rubella (MMR) vaccine.

But the level of population-wide immunity needed to stave off outbreaks and protect vulnerable populations, about 95 percent, has sunk to less than 93 percent, suggesting the cases documented in 2026 are just the beginning.

Enclosed areas like airports and planes are extremely risky locations for disease transmission. The measles virus spreads via airborne droplets when an infected person coughs or sneezes.

Measles first invades the respiratory system, then spreads to the lymph nodes and throughout the body. As a result, the virus can affect the lungs, brain and central nervous system.

While measles sometimes causes milder symptoms, including diarrhea, sore throat and achiness, it leads to pneumonia in roughly six percent of otherwise healthy children, and more often in malnourished children.

While the brain swelling that measles can trigger is rare, occurring in about 1 in 1,000 cases, it is deadly in roughly 15 to 20 percent of those who develop it, while about 20 percent are left with permanent neurological damage such as brain damage, deafness or intellectual disability. 

It also severely damages a child’s immune system, making them susceptible to other potentially devastating bacterial and viral infections they were previously protected against.  

A significant measles outbreak that started last year in West Texas, primarily within a largely unvaccinated religious community, quickly spread across state lines to the rest of the country. Texas officials have recorded more than 760 cases since January 2025.

 Before MMR vaccines became available in the 1960s, measles caused epidemics with up to 2.6 million global deaths every year. By 2023, that number had fallen to roughly 107,000 deaths.

The World Health Organization estimates that measles vaccination prevented 60 million deaths between 2000 and 2023. 

Robert F Kennedy, Jr, in his capacity both as current head of the Department of Health and Human Services and as co-founder of the nonprofit Children’s Health Defense, has consistently cast doubt on the safety and efficacy of well-studied vaccines such as the MMR shots. 

After the death of an eight-year-old girl in Texas, Kennedy acknowledged the MMR vaccine is the most effective way to prevent measles, while at the same time promoting vitamin A as an effective treatment, which is believed to have contributed to several small children being hospitalized with an overdose. 

High-dose vitamin A is a standard, evidence-based treatment for measles, proven to reduce the risk of death and severe complications like pneumonia. Its life-saving effect is most pronounced in individuals with pre-existing vitamin A deficiency.