Previously, experts believed the risk of subacute sclerosing panencephalitis, an always-fatal complication of measles, was one in 100,000. New research has put the risk closer to one in 600 for infants who contract measles prior to being vaccinated.
SSPE is a neurological condition that develops when someone gets the measles virus, which then spreads to the brain, when it becomes dormant. When it reactivates, it can lead to SSPE.
SSPE has no cure — the only way to prevent it is through herd immunity.
Researchers found 17 SSPE cases in California between 1998 and 2015, and everyone who developed SSPE had a prior measles infection. When they analyzed it further, they found 1 in 609 California children under 12 months old developed SSPE — too young to be vaccinated.
"This is really alarming and shows that vaccination truly is life-saving," said James Cherry, MD, an author of the study that was presented at IDWeek. "Measles is a disease that could be eliminated worldwide, but that means vaccinating at least 95 percent of all who are eligible with two doses of measles vaccine in order to protect everyone, including those who aren't old enough to get the vaccine."