Measles is making a significant comeback. Just because the rash goes away doesn’t mean the danger is over.
Last year, the number of cases surged in the United States, with the Centers for Disease Control and Prevention reporting the highest incidence of this highly contagious respiratory virus in over 30 years.
And it’s still on the rise. In the first two weeks of 2026, at least 171 people across nine states were reported to be infected, according to federal data.
Measles symptoms often mimic those of a common cold at first, including a cough, runny nose, sore throat, and watery eyes, but can escalate quickly to a high fever followed by a distinct red rash that covers the body.
The most frequent complication is pneumonia. However, another serious threat lurks that many might not be aware of: a fatal neurological disease that can emerge decades after the initial infection.
Dr. Sharon Nachman, director of pediatric infectious diseases at Stony Brook Children’s Hospital, explained that “measles kind of stays in the brain, causing changes at the cellular level, sitting there silently. Then, 10, 20 years later, it comes and destroys the brain.”
This unusual but severe complication is known as Subacute sclerosing panencephalitis (SSPE). It often begins with minor personality shifts like memory loss, irritability, and mood fluctuations, advancing over time to muscle spasms, loss of coordination, severe brain damage, coma, and ultimately death.
The incidence of SSPE is between 4 and 11 cases per 100,000 people with measles, with the risk rising to 18 per 100,000 for children infected before age five.
“Imagine having measles as a toddler, and then, years later, as a college student, your future is abruptly shattered,” Nachman said. “People wonder, ‘How did this happen?’ They don’t connect it to the measles they had years ago.” She referred to it as “the gift that keeps on giving.”
There’s no known cure for SSPE, and around 95% of those affected do not survive. Some treatments may slightly slow its progression, but the prognosis remains grim.
Typically, only four to five cases of SSPE occur annually in the U.S., but that number is likely to rise alongside increasing measles infections.
“Current records of measles cases are just the tip of the iceberg; we estimate undocumented cases are at least three times as high, so just think about how many cases might arise in the coming years,” Nachman said.
The effects are already evident. Last year, a school-age child in Los Angeles developed SSPE and passed away after contracting measles as an infant, prior to being old enough for the measles, mumps, and rubella (MMR) vaccine.
The MMR vaccine is 97% effective against measles, and it’s recommended for children at 12 to 15 months, with a follow-up dose before they enter kindergarten.
Dr. Muntu Davis, an LA County Health Officer, emphasized that “infants too young to be vaccinated rely on community immunization for their protection.” He added, “Vaccination is about safeguarding not just yourself but your family, neighbors, and vulnerable children.”
However, vaccination rates in the U.S. have declined since the COVID-19 pandemic. Recent reports showed that only 92.5% of kindergarteners received their MMR vaccine during the 2024-25 school year, down 2.5% since 2019-20.
This figure falls well below the 95% threshold needed to stave off outbreaks.
Some argue that the drop in vaccination rates stems from fraudulent studies falsely linking the MMR vaccine to autism, a narrative that has been widely debunked. Misinformation on social media is likely contributing to vaccine hesitance, particularly in the wake of pandemic-related skepticism.
While side effects of the MMR vaccine are usually mild—such as a rash, fever, and soreness at the injection site—severe reactions can occur, like allergies and neurological issues.
In the previous year, the CDC documented 2,242 measles cases in the U.S., with 93% occurring in those unvaccinated or lacking confirmed vaccination status. Among these cases, 245 individuals were hospitalized, and three lost their lives.
