AIM: To assess the impact of measles/mumps/rubella (MMR) vaccine on the 
epidemiology of subacute sclerosing panencephalitis (SSPE) in England and Wales.
METHODS: Cases of SSPE resident in England and Wales with onset between 1990 and 
2002 were reviewed.
RESULTS: A total of 47 cases were identified, 31 male and 16 female. There was 
an average annual decline of 14% in SSPE onset over the period, consistent with 
the decline in notified measles over the last 20 years. A history of measles was 
present in 35 (median age 1.3 years), the most recent recorded date being 1994; 
the interval from measles to onset of SSPE ranged from 2.7 to 23.4 years. Four 
children with a history of receipt of a measles containing vaccine were reported 
not to have had measles; two of these cases had a brain biopsy, and nucleotide 
sequence data confirmed wild measles infection. Brain biopsy specimens from a 
further three cases with a history of measles, of whom two had also had a 
history of vaccination, showed wild-type strain.
CONCLUSION: The prevention of endemic circulation of measles virus in England 
and Wales through the high coverage achieved with MMR vaccine, together with the 
measles/rubella vaccination campaign of 1994, has resulted in the near 
elimination of SSPE. However, the recent decline in MMR vaccine coverage, with 
the associated increase in localised measles outbreaks and cases in young 
infants, is of concern. It underlines the importance of maintaining high vaccine 
coverage in order to protect indirectly those most vulnerable to SSPE, namely 
infants too young to be vaccinated.