A deadly measles complication that kills kids years after they seemingly recover may not be as rare as doctors thought, researchers said Friday.
The fatal and incurable complication has killed at least 16 California adults and children, the researchers in Los Angeles and San Francisco said.
They say they’re afraid the condition is far more common than anyone thought, and say it strongly reinforces the need for vaccinating every single child who can be.
“This is really frightening,” said Dr. James Cherry of the University of California, Los Angeles medical school.
The victims all had a condition called subacute sclerosing panencephalitis or SSPE. It’s caused when the measles virus stays in the brain, usually for years, after a young child is infected and has recovered.
For reasons that no one understands, it can reawaken and causes an immune response that leads to seizures, coma and death. There’s no treatment and no one has been known to survive it.
“It takes having had measles many years before."
Once thought very rare, a recent study in Germany and now the California study suggest SSPE is far more common than previously believed. Original estimates suggested it affected 1 in 100,000 kids, but in the California cases 1 in 600 people who got measles as infants developed SSPE, the researchers said.
They said 1 in 1,400 kids under 5 who got measles developed SSPE.
“Not only is SSPE still here and still diagnosed but it actually may be more common than we thought it was,” said Dr. Gary Marshall of the University of Louisville School of Medicine, who was not involved in the study.
Cherry says the cases involve people infected with measles since a major outbreak in the U.S. that started in 1988. Between 1989 and 1991, 55,000 measles cases were reported and 123 children died. Since then rates have been just a fraction of that and measles was declared eliminated in the U.S.
Let our news meet your inbox. The news and stories that matters, delivered weekday mornings.
Still, up to several hundred are reported every year when travelers bring measles back from other countries and occasionally spark small outbreaks.
The team started to look at possible SSPE cases after the German cases were reported. They found 16 people in California alone killed by SSPE – all diagnosed by autopsy after they died. A 17th case is in hospice care now, they told a meeting of infectious disease specialists in New Orleans.
The team found 17 cases of SSPE reported in California between 1998 and 2015. The average age was 12 but three were adults, aged 20, 30 and 35. Every one had measles before getting vaccinated and the researchers say there is no evidence the measles vaccine can cause SSPE.
“It takes having had measles many years before,” Cherry said.
Many more cases across the country may have gone unreported, Cherry says.
The researchers say the findings reinforce the need to make sure children get two doses of the measles, mumps and rubella (MMR) vaccine as recommended by the Centers for Disease Control and Prevention.
“Parents of infants who have not yet been vaccinated should avoid putting their children at risk."
Because babies younger than 1 cannot be vaccinated, populations around them need to be fully vaccinated to protect them.
The U.S. has a small but heated controversy over vaccinating children. Health experts say pockets of well-meaning and well-to-do vaccine doubters can help fuel outbreaks when they delay vaccination or refuse to vaccinate their kids at all.
The latest outbreak affected Disney theme parks in 2014 and 2015 and spread to a half-dozen U.S. states, Mexico and Canada. The outbreak sickened 147 people in the U.S., including 131 in California. No one died.
Globally, there are around 20 million cases of measles and more than 145,000 children die of measles every year.
“Parents of infants who have not yet been vaccinated should avoid putting their children at risk,” Cherry said. “For example, they should postpone trips overseas – including to Europe – where measles is endemic and epidemic until after their baby has been vaccinated with two doses. It’s just not worth the risk.”
Maggie Fox is a senior writer for NBC News and TODAY, covering health policy, science, medical treatments and disease.