NBC News
The number of measles cases reported this year is more than triple the total for 2023, and there are still five months left in 2024. According to data released Friday by the Centers for Disease Control and Prevention (CDC), 188 cases have been reported in 26 states and Washington, D.C.
No deaths have been reported, but 93 people have been hospitalized, mostly children under 5 years old.
The United States has had 13 measles outbreaks this year, the largest of which occurred in March at a migrant shelter in Chicago, where 60 cases were reported.
This month, measles cases have been reported in Massachusetts, Michigan, Minnesota, New Hampshire, New York, Oregon and Vermont. The Massachusetts case was the first in that state since early 2020.
Last year there were only four measles outbreaks in the United States and 58 cases in total.
This year’s tally is the highest since 2019, when the country nearly lost its measles elimination status. Most of the more than 1,200 cases that year were linked to outbreaks in Orthodox Jewish communities in New York.
“This year could be even worse than 2019 — there’s certainly the potential for that,” said Dr. David Hamer, a professor of global health and medicine at Boston University’s School of Public Health. But CDC models suggest that’s highly unlikely.
Experts attribute this year’s increase to two main factors: declining vaccination rates in the United States and a rise in measles cases worldwide.
About 85% of people who got measles this year were unvaccinated or had unknown vaccination status, according to the CDC. Many of the cases have been linked to international travel, meaning the disease was brought into the country by travelers who were infected abroad.
“We live in a global community where vaccination rates everywhere have an impact on the diseases that are transmitted in the United States,” said Dr. Erica Prochaska, a pediatric infectious disease specialist at Johns Hopkins Children’s Center. “But the bigger problem is that in the United States, our population is not at the vaccination threshold that we should be.”
A person infected with measles can transmit the disease to up to 90% of those close to them if those contacts are not immune. That’s why public health officials recommend that communities have at least 95% vaccination coverage to prevent continued transmission.
By the 2022–23 school year, 93% of kindergartners in the United States had received two doses of the measles, mumps, and rubella (MMR) vaccine, down from 95% in the 2019–20 school year. Twelve states and Washington, D.C., had rates below 90%.
“What surprises me is that the outbreaks aren’t more widespread,” said Dr. Gregory Poland, founder and director of the Mayo Clinic Vaccine Research Group.
She added that some immunocompromised people are not eligible for the MMR vaccine (for measles, mumps and rubella), “so they are dependent on the rest of us getting two doses.”
Vaccine use is declining
The United States eliminated measles in 2000, meaning the disease is no longer present all the time, although there are occasional outbreaks originating in other countries. Before the first measles vaccine became available in 1963, about 3 to 4 million people in the United States were infected each year, and 400 to 500 people died from the disease annually.
“Somehow people don’t see it as a big problem anymore,” Hamer said.
Vaccine hesitancy, fueled by misinformation during the pandemic, has contributed to the problem, he added.
Globally, measles vaccination coverage fell during the pandemic to the lowest levels since 2008.
Hamer added that lockdowns disrupted vaccination services in many low- and middle-income countries, and ongoing civil wars may have hampered vaccination efforts in countries such as Ethiopia and Yemen, which account for a disproportionate share of global measles cases.
“The end result was that many countries that were on the borderline in terms of having adequate coverage dropped their coverage of routine childhood vaccines, including measles,” Hamer said.
From 2021 to 2022, measles cases increased by 18% and measles deaths increased by 43% worldwide, according to a joint report by the CDC and the World Health Organization. The number of countries experiencing large or significant outbreaks increased from 22 to 37 during that time.
Common symptoms of measles include high fever, cough, conjunctivitis (red eyes), runny nose, white patches in the mouth, and a rash that spreads from head to toe. Between 1 and 3 out of every 1,000 children infected with measles die from complications such as pneumonia or inflammation of the brain.
