The first sign came when Deepanwita Dasgupta was five and started stumbling more while playing at her home in Bangalore in southern India. The girl was always up to something, so her parents figured extra bumps and bruises were just symptoms of an active childhood. Maybe, they thought, it was ill-fitting shoes.
Relatives described the unicorn-loving child as smart, affectionate, and occasionally rascally. Before she learned the alphabet, she had figured out how to find her favorite show, Blippi, on a phone. She was known to sneak butter from the fridge to enjoy a few finger licks.
But then her limbs started jerking. A spinal tap revealed measles in her cerebrospinal fluid. The virus she probably contracted as an infant had secretly made its way to her brain. Now eight years old, Deepanwita is paralyzed and unable to talk.
Measles causes complications, ranging from diarrhea to death, in three in ten infected patients, according to the Infectious Diseases Society of America. Some are immediate, while others take weeks or months to appear. The one Deepanwita is experiencing, subacute sclerosing panencephalitis, or SSPE, typically takes years to emerge.
“People think, ‘Oh, you know, if we get measles, then we’ll be fine, because I know my neighbor had it and they’re fine,’” said Yasmin Khakoo, MD, who leads the national Child Neurology Society but spoke to KFF Health News in her capacity as a New York City physician with expertise in neurologic conditions.
Measles, though, can be dangerous: A seven-year-old in South Carolina will have to relearn how to walk following one of the more immediate complications, brain swelling. In rare cases, the virus can remain dormant in the nervous system. A patient can recover from measles and continue life as usual, no longer contagious and without any identifiable symptoms, sometimes for a decade or more, before problems appear. While some patients end up severely disabled for a period of time, Khakoo said, the condition is almost always fatal.
Before the advent of widespread and effective vaccines, the complication occurred often enough in the US that in the 1960s a physician created a national registry of SSPE patients. Researchers now estimate about one in 10,000 patients who get measles will develop SSPE, but the risk is significantly higher for those who contract measles before age five. Populous nations where the virus is endemic, including India, see cases routinely.
Now, physicians and researchers fear that as vaccination rates drop and measles spreads in the US, cases of this debilitating complication will also rise. Since the start of 2025, the Centers for Disease Control and Prevention has recorded over 3,500 measles cases, more than in the entire preceding decade, mostly among patients who were unvaccinated. Many were children. Last year, Connecticut physicians diagnosed a six-year-old with SSPE, and in California, a school-age child who had contracted measles as an infant died of it.
“We are likely to see SSPE cases going forward, especially if we don’t get this under control,” said Adam Ratner, MD, a member of the American Academy of Pediatrics’ Committee on Infectious Diseases and author of the book Booster Shots.
Concern about SSPE was great enough that in January, the Child Neurology Society published a video to educate US clinicians about the condition, and physicians who have seen such cases are warning their peers.
“We don’t have a way of knowing who’s going to get it, and we don’t have a way of very effectively treating it,” said Aaron Nelson, MD, a professor of neurology with the New York University Grossman School of Medicine. “The one best thing that we can do, ideally, is to prevent children from having to go through it in the first place.”
The recommended two-dose measles vaccine reduces an exposed person’s risk of contracting the contagious virus from 90% to 3% and thus reduces the chance of SSPE. The vaccines carry small risks of febrile seizure and a bleeding condition, but measles itself has a higher risk of causing both.
KFF Health News is a national newsroom that produces in-depth journalism about health issues and is one of the core operating programs at KFF—an independent source of health policy research, polling, and journalism. Learn more about KFF.
