Subacute sclerosing panencephalitis ( SSPE) is a rare, fatal complication from measles infection, occurring in about 1 in 10 000 measles cases. Generally the condition affects people who contracted measles before the age of 2. Patients appear to recover from their measles infection, only to be struck by this complication 6 to 15 years after the initial infection.
Apparently in people with SSPE the measles vaccine infects the brain cells, where it avoids triggering an immune response. It causes behaviour changes, memory loss, loss of bodily control, seizures, coma and death. If caught in stage 1, the disease can be treated, but requires life long medication to prevent the disease from advancing. For those who progress to stage 2, death occurs in about 3 years.
This is what antivaxxers as risking in their children. They are also risking this condition in other people's children, when they let their kids expose children too young to be vaccinated to the measles. I heard the sister of a teenaged boy who developed SSPE on the radio this morning and thought that this is something that definitely needed repeating.
After they talked to the sister, they also talked to an antivaxxer who tried to blame his death in something else. Thankfully Anna Maria Tremonti held the anti-vaxxer's feet to the fire. It was awesome.