Recent outbreaks of measles in the United States are driving up case counts and raising alarm among public health experts, especially as vaccination rates among children lag.
The concern this year comes after the first reported deaths in the US since 2015 and following a significant increase in the number of cases in 2024.
General symptoms may include fever, cough, runny nose, watery eyes and a rash of red spots. About 1 in 5 unvaccinated people in the US who get measles will be hospitalized, according to the CDC.
About 1 in every 20 children will develop pneumonia, and others may develop a dangerous swelling in the brain called encephalitis. Up to 3 of every 1,000 children who become infected with measles may die from respiratory and neurologic complications.
Measles is preventable, thanks to a highly effective vaccine. Experts recommend that children get the measles, mumps and rubella, or MMR, vaccine in two doses: the first between 12 months and 15 months of age, and a second between 4 and 6 years old. One dose is about 93% effective at preventing measles infection; two doses are about 97% effective.
The current outbreak “is absolutely being driven and started by unvaccinated individuals,” said Dr. Michael Mina, chief scientific officer of the telehealth company eMed and an expert in the epidemiology, immunology and spread of infectious disease.
The increased concern about measles cases can be attributed to falling vaccination rates and to increased travel, which can result in unvaccinated people acquiring measles abroad and bringing it back to the US, according to the CDC, which occurred in 2019.
Here’s how the cases this year compare to the past.
Measles is preventable, thanks to a highly effective vaccine. Experts recommend that children get the measles, mumps and rubella, or MMR, vaccine in two doses: the first between 12 months and 15 months of age, and a second between 4 and 6 years old. One dose is about 93% effective at preventing measles infection; two doses are about 97% effective.
The current outbreak “is absolutely being driven and started by unvaccinated individuals,” said Dr. Michael Mina, chief scientific officer of the telehealth company eMed and an expert in the epidemiology, immunology and spread of infectious disease.
“If a measles outbreak continues for a year or more, the United States could lose its measles elimination status,” according to the CDC.
Because measles is so contagious, a high level of vaccination coverage is key to minimizing spread. The US has set a target vaccination rate of 95%, but coverage among kindergarteners has dipped below that in recent years.
MMR vaccine series completion among kindergarteners decreased from 95.2% during the 2019–2020 school year to 92.7% in the 2023–2024 school year, leaving about 280,000 at risk, according to the CDC.