By Deidre McPhillips, CNN
(CNN) — The United States reported a record number of measles cases in 2025, and the virus continues to spread rapidly in the new year. At least 171 measles cases have been reported in the first two weeks of 2026, according to data published Wednesday by the US Centers for Disease Control and Prevention – nearly as many as the average annual total in the 25 years since measles was declared eliminated.
Most of the new cases are concentrated in areas with large ongoing outbreaks — in the upstate region of South Carolina and along the Utah-Arizona state line — but the sheer scale of those outbreaks leaves the broader public at risk, even in places that aren’t currently reporting high numbers of cases.
As measles cases grow exponentially, it becomes harder to track every exposure, said Dr. Linda Bell, South Carolina’s state epidemiologist. People may also be out in the community without knowing that they’re infectious, and this can lead to unknown exposures.
Dozens of public exposure locations have been identified in South Carolina over the past week, Bell said Wednesday — at schools, churches, restaurants, shops and health care settings — but the health department doesn’t always publicize all of those exposure locations unless it can share specific details about the date and time of the occurrence.
Exposures can happen when people are visiting areas experiencing an outbreak, as happened with a North Carolina family who visited Spartanburg County, South Carolina, and when infected individuals travel, as in New Mexico, where the health department recently warned of possible measles exposure at a hotel in Albuquerque from someone visiting from South Carolina.
At least four major international airports in the US reported measles cases or potential exposures during peak holiday travel last month, and an infectious individual traveled through major cities in the Northeast on an Amtrak train last week.
“We’re going to see more of those exposures” because of falling vaccination rates and greater spread, said Dr. Jesse Hackell, a retired pediatrician and member of the American Academy of Pediatrics, but “vaccinating almost completely eliminates the risk of an exposure leading to disease.”
Here’s how to prepare for a possible measles exposure and how to respond if it happens.
Check your vaccination status
Measles is one of the most contagious diseases there is, but the measles-mumps-rubella (MMR) vaccine is extremely effective. One dose is 93% effective against measles, and the recommended second dose bumps that protection up to 97% — and the immunity is lifelong.
It’s generally recommended that children get their first dose around 12 months to 15 months of age and the second between ages 4 and 6, but that timeline can move earlier amid outbreaks — with the first dose given as young as 6 months. Older children and adults can get vaccinated at any time, too.
People who are vaccinated don’t have much to worry about, experts say.
“If you have immunity to measles, you will most likely just be directed to watch for symptoms as a precaution,” said Dr. Raynard Washington, director of the public health department in Mecklenburg County, North Carolina. “The vaccine should do what it is intended to do.”
For people who are not vaccinated when they’re exposed to the virus, there still is a chance to benefit from the protection the vaccine provides — but quick action is required.
An MMR vaccine given within 72 hours of exposure to measles may offer some protection or lead to milder illness. This timeframe is often before symptoms appear.
Contact your health care provider
People who know that they have been exposed to measles, or who are worried that they might have been exp