Deadly brain disorder can develop a decade after measles infection

A school-aged child in L.A. recently died after developing a rare neurological disease years after contracting the measles.

Authorities didn’t reveal many details about the case, except that the child was infected with measles as an infant, before they were eligible for the vaccine.

Measles is a respiratory disease that spreads easily from person to person. The first dose of the measles, mumps and rubella (MMR) vaccine is routinely recommended for kids between 12 and 15 months old. A second dose is given before kindergarten or first grade.

Pneumonia is the most common complication of measles — the infection can also lead to bronchitis, laryngitis, and, in very rare but severe cases, like the child in L.A. County, subacute sclerosing panencephalitis (SSPE).

After the initial infection, the measles virus can persist in the body and acquire certain mutations that trigger SSPE years later.

Out of every 100,000 cases of measles, four to 11 patients typically develop SSPE.

The disease can progress from mood changes to involuntary muscle spasms, writhing, twisting movements, severe brain damage and death.

Symptoms typically emerge six to 10 years after the original infection.

There are usually only about four or five SSPE cases in the US each year — though this number is expected to rise as measles cases increase.

The SSPE mortality rate is 95% as there is no known cure. Antiviral and anti-inflammatory drugs may slow disease progression.

The L.A. child is one of three measles-related deaths reported this year by the Centers for Disease Control and Prevention.

“This case is a painful reminder of how dangerous measles can be, especially for our most vulnerable community members,” L.A. County Health Officer Dr. Muntu Davis said in a statement last week.

“Infants too young to be vaccinated rely on all of us to help protect them through community immunity,” the statement continued. “Vaccination is not just about protecting yourself — it’s about protecting your family, your neighbors and especially children who are too young to be vaccinated.”

Inoculation rates for the MMR vaccine and other routine childhood immunizations have declined in the US since the COVID-19 pandemic.

A recent report found that 92.5% of kindergarteners had been vaccinated against MMR for the 2024-25 school year, a decrease from 95% for the 2019-20 school year.

“Declining vaccination rates stem partly from fraudulent research attempting to link the MMR vaccine to autism — claims by a now-discredited doctor that have been thoroughly debunked,” Benedict Michael, a professor in infectious neuroscience at the University of Liverpool in the UK, wrote this week in The Conversation.

“Social media misinformation has amplified these fears, potentially worsened by COVID pandemic skepticism around vaccines.”

Michael noted that the MMR vaccine is 97% effective, preventing over 60 million deaths worldwide between 2000 and 2023. 

MMR vaccine side effects may include a mild rash, fever, swollen glands in the neck, cheeks and jaw, and soreness or redness at the injection site.

In rare cases, recipients may experience allergic reactions, seizures, a neurological disorder called Guillain-Barré syndrome or spinal cord inflammation.

The CDC is reporting 1,491 measles cases so far this year, as of Wednesday. About 92% of patients were unvaccinated or their vaccination status was not known.

Twelve percent of cases led to hospitalizations. Most of these patients were kids younger than 5.

“The death in L.A. serves as an important reminder that measles is not a benign childhood illness,” Michael wrote.

“It can cause serious complications, including pneumonia and, as this case shows, delayed but deadly brain damage years later.”