MMR (measles

Deadly measles complication is more common than thought, study says

Researchers figured this out by looking at records of people who had a neurological disease called subacute sclerosing panencephalitis, or SSPE, in California between 1998 and 2016. The research was presented at IDWeek, an infectious-disease conference, in October.

SSPE is a neurological complication from measles in which, essentially, the body has an abnormal immune response to the virus.