CDC urges summer camps to check for measles immunity, as U.S. nears record

The U.S. Centers for Disease Control and Prevention is now urging summer camp operators to check for documentation of immunity from measles through vaccination or prior infection for all children, staff and volunteers, amid a deadly year of outbreaks that is now near record levels.

"Measles can spread quickly in summer camps because campers and staff spend a lot of time together in close contact with each other. Measles is more than just a rash — it can cause serious complications or even death," the CDC warned in a "checklist" for operators of summer camps published this week.

The agency's new guidance says that tracking measles immunity status is important to help health departments quickly identify people who need to be vaccinated or offered antibody injections in the case of an outbreak within a camp.

"Decide if you will allow unvaccinated campers and staff at your camp. Understand the risk if you do accept a camper or staff member who has not been immunized for measles," the American Camp Association says in its guidance for camps, which shared the CDC's checklist.

Other steps that the CDC recommends summer camps take to prepare for measles spread this year include stocking up on face masks and preparing a potential isolation space to separate campers who are sickened.

The CDC's new recommendations come as confirmed measles cases have climbed to 1,197 infections so far in 2025, less than 100 cases away from topping the record 1,274 cases that were confirmed for all of 2019. That marked a record since the U.S. in 2000 declared uncontrolled community spread of the virus eliminated through widespread measles vaccinations.

At the time in 2019, health officials said the total number of cases added up to the worst tally on record since the 20th century.

This year's wave is already deadlier than the 2019 wave of outbreaks, which health officials and experts suspect is due to missed infections that have gone unreported.

In 2019, summer camps in New York tightened their vaccination requirements amid record outbreaks in the state among underimmunized communities. In response to the outbreaks, then-New York Gov. Andrew Cuomo signed a law that year removing religious exemptions from measles vaccination requirements for school and child day care programs.

About two in three confirmed measles cases this year have been in children or teens, according to the CDC's tally. Most have been linked to local outbreaks within the U.S., many from the outbreak in Texas and neighboring states earlier this year.

While new cases around Texas slowed in April, preliminary CDC data from recently reported measles cases — backdated to when patients' symptoms began — suggests the pace of new infections nationwide began accelerating again in May.

The agency also recently stepped up its warning about the risk of catching measles while traveling. The new guidance followed dozens of cases of travelers infectious while flying on airplanes within the U.S., and a suspected case of spread during air travel, CBS News previously reported.