Subacute sclerosing panencephalitis

Subacute sclerosing panencephalitis is a rare form of progressive brain inflammation caused by a persistent infection with a mutated wild type strain of the measles virus, arising years after a person has apparently recovered normally from the original measles infection rather than from any vaccine strain. Symptoms typically appear about ten years after the initial infection, though the interval can range from one month to 27 years, and the disease progresses through four stages marked by behavioral changes, seizures, vision loss, coordination problems and eventual loss of consciousness. Following the onset of the second stage the disease is invariably fatal, with death typically occurring within months to years and spontaneous remission occurring in only about five percent of cases. About two in 10,000 measles cases develop the condition, with unvaccinated infants under 15 months facing a substantially higher risk of roughly one in 609.