As measles continues to spread in the United States, it’s likely that the outbreaks that broke records in 2025 will continue into the new year.
In South Carolina, 168 people, mostly schoolchildren, are in quarantine. Most of the state's 138 cases confirmed since September, nearly all in unvaccinated people, have been centered in Spartanburg County in the northwestern part of the state.
“As we identify new cases, and if those cases have susceptible contacts, that’s a new 21-day quarantine period,” Dr. Linda Bell, state epidemiologist for the state Department of Public Health, said Wednesday at what has become a weekly news briefing.
That is, anyone who is unvaccinated and therefore vulnerable to measles exposures occurring now will be in quarantine through the holidays.
According to NBC News data, the K-12 vaccination rate for measles-mumps-rubella (MMR) in Spartanburg County was 90% for the 2024-25 school year, below the 95% level doctors say is needed to protect against an outbreak.
Bell said the vaccination rate has been falling for several years, similar to other areas in the United States.
Based on NBC News' investigation, The Vaccine Divide, in the states collecting data for the MMR vaccine, 67% of counties and jurisdictions have immunization rates below 95%.
Bell said at the briefing that there was no indication the South Carolina outbreak was spreading yet to nearby states, such as North Carolina.
Since the latest surge in cases, which began in late summer in the bordering areas of southwestern Utah and Arizona and, more recently, in South Carolina, the Centers for Disease Control and Prevention has taken a low profile, with nearly all public outreach about the nationwide outbreaks coming from local and state health departments.
It’s a stark contrast to how the agency has previously communicated about infectious diseases like measles.
A study published last week uncovered an “emerging health communication void” regarding measles and measles vaccines in the CDC’s social media accounts. The agency posted about measles 10 times on its social media channels from January through August, according to the study.
During the same period from 2021 to 2024, the CDC posted an average of about 46 times each year, the study found.
Andrew Nixon, a spokesman for the Department of Health and Human Services (which oversees the CDC), said in an email that the “CDC has developed and distributed updated communication materials, including multilingual resources, to help communities respond to ongoing outbreaks.”
The CDC sends teams to investigate infectious disease hot spots only if states request it. Bell said the South Carolina Public Health Department hasn’t asked for extra help from the agency to contain the outbreak.
Separately, the measles outbreak largely straddling the border between Arizona and Utah also continues to swell.
The Utah Department of Health and Human Services reports 125 cases, with 21 diagnosed just in the last three weeks. According to the health department, there were multiple measles exposures last week in the southwestern part of the state, including at an elementary school, an urgent care facility, a pediatrician’s office and a pediatric dentistry.
The Arizona Department of Health Services reports 190 cases, nearly all in Mohave County, which borders Utah.
Nearly all of those cases, 97%, occurred among people who weren’t vaccinated against the virus.
As of Wednesday, the United States had logged 1,958 measles cases in 2025, according to the latest update from the CDC. That’s just 168 cases shy of a previous high of 2,216 recorded in 1992.
There have been 49 outbreaks (defined as three or more related cases) reported in 2025. In 2025, 222 people, 11% of the 1,958 cases, were sick enough to be hospitalized, according to the CDC.
Three people, an adult in New Mexico and two young girls in Texas, have died.
