Frequency, serodiagnosis and epidemiological features of subacute sclerosing panencephalitis (SSPE) and epidemiology and vaccination policy for measles in the Federal Republic of Germany (FRG).

In the FRG, SSPE, a slow infection of the brain in children and young adults, known to be associated with a chronic measles virus infection, has an estimated incidence of 2.6 cases per million total population (61 million) and 9.7 cases per million population below the age of 19 years (16 million). In the 156 SSPE cases between 1968 and 1977 the characteristic clinical, epidemiological and serological features were found. Measles antibodies were present in the CSF and the serum titers as measured in conventional (CF--HI--IFA) and new (RIA and ELISA) tests were significantly higher than those in siblings, parents, age-matched controls as well as in patients with recent measles or after live measles vaccination. Only in children with recent wild virus infection after previous vaccination with inactivated Split measles vaccine were similar elevated serum antibody levels observed. In the SSPE cases as well as in the former group, antibodies of the IgM-class were seldom detectable and isolation of infectious measles virus from brain tissue and lymphnode derived cell cultures was rarely accomplished. The search for a co-factor or triggering agent of SSPE such as inactivated or live measles virus vaccination, concomitant childhood infection or vaccination with onset of measles or SSPE was inclusive. The seroepidemiological observation of higher frequency and titer levels of EBV- and toxoplasmosis antibody in SSPE patients as compared to siblings and parents and the suspicion that arbor virus infection may have some influence on triggering SSPE must be further substantiated. It appears that this relatively rare disease arises after an early, normal measles infection in an immunologically competent child without special genetic characteristics, mainly belonging to the lower socio-economic group, by a change of the measles virus and the immune response of the host.