Just over 2 months into 2024, measles cases in the United States aren’t looking great.
The recent rise in cases across the U.S. is linked to unvaccinated travelers, lower than ideal vaccination rates, and misinformation, experts said.
The Centers for Disease Control and Prevention has identified 45 cases of measles in 17 jurisdictions across the U.S. As of March 7, the federal health agency reported measles cases in Arizona, California, Florida, Georgia, Illinois, Indiana, Louisiana, Maryland, Michigan, Minnesota, Missouri, New Jersey, New York City, Ohio, Pennsylvania, Virginia, and Washington.
As for the 45 cases, “that’s almost as many as we had for the entire calendar year of 2023,” said Sarah Lim, MD, a medical specialist at the Minnesota Department of Health. “So we’re really not off to a great start.” (For context, there were 58 officially reported measles cases last year.)
Chicago is having a measles outbreak — with eight cases reported so far. All but one case has been linked to a migrant child at a city shelter. Given the potential for rapid spread — measles is relatively rare here but potentially very serious — the CDC sent a team of experts to investigate and to help keep this outbreak from growing further.
Sometimes Deadly
About 30% of children have measles symptoms and about 25% end up hospitalized. Complications include diarrhea, a whole-body rash, ear infections that can lead to permanent deafness, and pneumonia. Pneumonia with measles can be so serious that 1 in 20 affected children die. Measles can also cause inflammation of the brain called encephalitis in about 1 in 1,000 children, sometimes causing epilepsy or permanent brain damage.
As with long COVID, some effects can last beyond the early infection. For example, measles “can wipe out immune memory that protects you against other bacterial and viral pathogens,” Dr. Lim said at a media briefing sponsored by the Infectious Diseases Society of America. This vulnerability to other infections can last up to 3 years after the early infection, she noted.
Overall, measles kills between 1 and 3 people infected per thousand, mostly children.
Vaccine Misinformation Playing a Role
Vaccine misinformation is partly behind the uptick, and while many cases are mild, “this can be a devastating disease,” said Joshua Barocas, MD, associate professor of medicine in the divisions of General Internal Medicine and Infectious Diseases at the University of Colorado School of Medicine.
“I’m a parent myself. Parents are flooded with tons of information, some of that time being misinformation,” he said at the media briefing. “If you are a parent who’s been on the fence [about vaccination], now is the time, given the outbreak potential and the outbreaks that we’re seeing.”
Vaccine misinformation “is about as old as vaccines themselves,” Dr. Lim said. Concerns about the MMR vaccine, which includes measles protection, are not new.
“It does seem to change periodically — new things bubble up, new ideas bubble up, and the problem is that it is like the old saying that ‘a lie can get halfway around the world before the truth can get its boots on.’ ” Social media helps to amplify vaccine misinformation, she said.
“You don’t want to scare people unnecessarily — but reminding people what these childhood diseases really look like and what they do is incredibly important,” Dr. Lim said. “It’s so much easier to see stories about potential side effects of vaccines than it is to see stories about parents whose children were in intensive care for 2 weeks with pneumonia because of a severe case of measles.”
Dr. Barocas said misinformation is sometimes deliberate, sometimes not. Regardless, “our job as infectious disease physicians and public health professionals is not necessarily to put the counternarrative out there, but to continue to advocate for what we know works based on the best science and the best evidence.”
“And there is no reason to believe that vaccines are anything but helpful when it comes to preventing measles,” he noted.