Morbidity and mortality of pneumococcal meningitis and serotypes of causative strains prior to introduction of the 7-valent conjugant pneumococcal vaccine in England.

OBJECTIVES: To assess the incidence of pneumococcal meningitis, associated deaths and serotypes of causative pneumococci in England prior to the inclusion of the 7-valent conjugated pneumococcal vaccine in the routine childhood immunisation programme in 2006.
METHODS: Cases were identified using hospital episode statistics (HES) and voluntary reports or submission of isolates to the Health Protection Agency. Mortality data and population estimates were from the Office for National Statistics.
RESULTS: Based on HES, the annual incidence of pneumococcal meningitis was about 1 case per 100,000 population between 1998 and 2005 (an average of approximately 480 cases per year) with case fatality rates increasing from 5% in <15 year olds to 30% in >64 year olds. Enhanced surveillance comprising a combination of voluntary reporting of cases and referral of isolates gave case ascertainment rates of 50-70% compared to those derived from HES, and similar case fatality rates. The age distribution of pneumococcal meningitis was similar with both datasets, infection being reported mostly commonly in children aged less than 5 years, with the highest incidence in children aged 2-11 months. Based on the serotype distribution of isolates obtained in 2005, the serotype coverage afforded by the 7-valent conjugate vaccine is 72% for patients aged less than 2 years.
CONCLUSIONS: These data provide baseline information on the incidence of pneumococcal meningitis and associated mortality, together with the serotypes of infecting strains of pneumococci, which will be critical for evaluation of the public health impact of the 7-valent conjugated pneumococcal vaccine in England.