Epidemiology of bacterial meningitis.

This 10 year retrospective study of all causes of bacterial meningitis for children resident in Nottingham District Health Authority area reports an annual incidence rate per 100,000 children aged 0-16 years of 16.0 (95% confidence interval 14.0 to 18.1). There was a steady increase in incidence from 9.6/100,000 in 1980 to 24.3/100,000 in 1989. This was mainly due to an increase in the incidence of meningococcal infections in the age group 1 month to 5 years. Incidence rates varied with age being: 37.2/100,000 (25.9 to 53.5) for 0-28 days of age, 115.5/100,000 (93.9 to 141.9) for 1-11 months of age, 28.5/100,000 (23.1 to 35.3) for 12-59 months of age, and 2.8/100,000 (1.9 to 4.1) for 5-16 years of age. Overall annual mortality incidence per 100,000 was 1.8 (1.2 to 2.8). For the different age groups this was: 10.1 (4.8 to 21.1) for 0-28 days, 11.5 (6.0 to 22.2) for 1-11 months, 1.0 (0.3 to 3.1) for 12-59 months, and 0.4 (0.1 to 1.2) for 5-16 years of age. There were interactions between the type of meningitis and the year of the infection on the mortality rate. Mortality decreased in those with infections caused by bacteria other than Neisseria meningitidis and Haemophilus influenzae.