Hospital admission rates for meningitis and septicaemia caused by Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae in children in England over five decades: a population-based observational study

Summary

Background

Infection with Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae causes substantial mortality and long-term morbidity in children. We know of no study to assess the long-term trends in hospital admission rates for meningitis and septicaemia caused by these pathogens in children in England. We aimed to do such a study using routinely reported data in England.

Methods

In this population-based observational study, we used datasets that include routinely collected administrative statistics for hospital care: the Hospital In-Patient Enquiry (data for England from 1968 to 1985), the Hospital Episode Statistics dataset (data for England from 1989 onwards), and the Oxford record linkage study (data for Oxfordshire and surrounding areas from 1963 to 2011). We analysed annual age-specific and age-standardised admission rates in children younger than 15 years with H influenzae, meningococcal and pneumococcal meningitis, and septicaemia.

Findings

We saw a reduction in hospital admission rates for childhood invasive bacterial disease after the introduction of conjugate vaccines against H influenzae, N meningitidis, and S pneumoniae in England. Annual incidence of H influenzae meningitis per 100 000 children decreased from 6·72 admissions (95% CI 6·18–7·26) in 1992 to 0·39 admissions (0·26–0·52) in 1994, after the introduction of routine H influenzae type b vaccination. We saw a small rise in admissions in the early 2000s, peaking at 1·24 admissions per 100 000 children (0·99–1·48) in 2003, which decreased to 0·28 per 100 000 children (0·17–0·39) by 2008 after the introduction of catch-up (2003) and routine (2006) booster programmes for young children. Meningococcal disease increased during the 1990s, reaching a peak in 1999, with 34·54 admissions (33·30–35·78) per 100 000 children. Hospital admissions decreased after the meningococcal serogroup C vaccine was introduced in 1999 and was 12·40 admissions (11·68–13·12) per 100 000 in 2011. Admissions for invasive pneumococcal disease increased from the 1990s reaching a peak in 2006 at 4·45 admissions for meningitis (95% CI 4·0–4·9) per 100 000 children and 2·81 admissions for septicaemia (2·45–3·17) per 100 000 children. A reduction in admissions occurred after the introduction of the pneumococcal conjugate vaccine in 2006: hospital admission rates in 2011 were 2·03 per 100 000 children for meningitis and 1·12 per 100 000 children for septicaemia.

Interpretation

Vaccine-preventable invasive bacterial disease in children has decreased substantially in England in the past five decades, most notably with the advent of effective conjugate vaccines since the 1990s. Ongoing disease surveillance and continued development and implementation of vaccines against additional pneumococcal serotypes and serogroup B meningococcal disease are important.

Funding

None.

Introduction

Haemophilus influenzae, Neisseria meningitidis, and Streptococcus pneumoniae can cause severe childhood disease and are associated with substantial mortality and long-term morbidity. Case-fatality rates in high-income countries for childhood bacterial meningitis caused by these pathogens are between 5% and 10%.1, 2 The median risk of long-term disabling sequelae in survivors of bacterial meningitis is about 20%, with such sequelae most likely after pneumococcal meningitis.3, 4

Unlike polysaccharide vaccines, conjugate vaccines are highly effective in children younger than 2 years and induce immunological memory responses, with protection boosted by subsequent doses.5, 6 In the UK, a conjugate vaccine against H influenzae type b (Hib) was introduced into the routine infant vaccination schedule with a catch-up programme in October, 1992.7, 8, 9, 10 N meningitidis causes septicaemia and meningitis. A serogroup C meningococcal conjugate vaccine was introduced in September, 1999, as three infant doses along with a catch-up campaign to 19 years of age after an increase in meningococcal serogroup C disease, the second most common serogroup causing disease in the UK at the time.11, 12 S pneumoniae causes a wide range of invasive disease including meningitis, bacteraemia, pneumonia, and bone and joint infection. The seven-valent pneumococcal conjugate vaccine (PCV7) was introduced in September, 2006, at months 2, 4, and 13 after birth with a catch-up programme to 2 years of age, and was replaced by the 13-valent pneumococcal vaccine from April, 2010.13, 14, 15

Findings from microbiological surveillance studies in the UK have shown a substantial reduction in invasive bacterial disease caused by H influenzae, N meningitidis, and S pneumoniae after the introduction of effective conjugate vaccines.7, 11, 16 However, long-term trends in hospital admission rates have not been reported. Here, we assessed trends for meningitis and septicaemia caused by these pathogens using hospital data for England from the 1960s to 2011.