The escalating measles cases in the U.S. in 2024 have taken the nation by surprise, exceeding the total count of the previous year. The sudden upsurge, primarily attributed to outbreaks in various regions, has alarmed public health officials and sparked a nationwide conversation on immunization.
On March 27, 2024, the Centers for Disease Control and Prevention (CDC) reported an unexpected rise in measles cases in the United States. The total count for the year had already exceeded the total for 2023, reaching 64 across 17 states by Thursday.
Multiple outbreaks have led to this early surge, with a significant outbreak in Chicago, an elementary school in Southeast Florida, and a children’s hospital and day care center in Philadelphia being the most affected areas.
Measles is a highly contagious disease. An infected person can spread it to up to 90% of people close to them if those contacts aren’t immune. Despite its elimination in the U.S. in 2000, sporadic outbreaks still occur.
The measles, mumps and rubella (MMR) vaccine is the most effective way to prevent measles. Two doses offer 97% effectiveness. However, the CDC has warned that “pockets of low [vaccination] coverage leave some communities at higher risk for outbreaks.”
Vaccination rates have seen a downward trend in recent years. For nearly a decade, 95% of U.S. kindergartners had received two doses of the MMR vaccine. That rate fell to 94% in the 2020–21 year, then to 93% in the 2022–23 school year.
Measles symptoms usually start with a high fever, cough, conjunctivitis (pink eye) and runny nose. Two to three days later, people may notice tiny white spots in their mouth. On days three to five of symptoms, a blotchy rash often forms at the hairline before spreading to the rest of the body.
Complications from measles can be severe, including pneumonia, swelling of the brain or a secondary bacterial infection. Before the measles vaccines became available in 1963, around 48,000 people were hospitalized and 400 to 500 people died of the disease each year in the U.S.
In 2019, the U.S. was on the verge of losing its measles elimination status, with most of the 1,249 cases that year associated with outbreaks in Orthodox Jewish communities in New York.
A significant number of measles cases reported in 2024 have been linked to international travel.
Most of the measles cases in 2024 have been among children who had not received the MMR vaccine. Today, 1 in 5 unvaccinated people who get measles are hospitalized, and roughly 1 to 3 out of every 1,000 children with measles die from respiratory and neurological complications, according to the CDC.
Community immunity, or herd immunity, occurs when a high percentage of the community is immune to a disease, making its spread from person to person unlikely.
Stay informed. Stay safe. Get vaccinated.
