Bacterial meningitis following introduction of Hib conjugate vaccine in northern Uganda

BACKGROUND: St Mary's Hospital, Lacor is in Gulu district in northern Uganda. Owing to conflict and insurgency, the majority of the hospital population live in internally displaced people's camps. There is ongoing public health surveillance of paediatric bacterial meningitis by the hospital. Before the introduction of Haemophilus influenza type b (Hib) conjugate vaccine in June 2002, Hib was the leading cause of bacterial meningitis in the area. METHODS: All patients with suspected bacterial meningitis between April 2003 and August 2006 were recruited. Meningitis was confirmed by isolation of bacteria. RESULTS: During the study period, 4986 cases of suspected bacterial meningitis were identified, 395 of whom had purulent cerebrospinal fluid (CSF). A culture was obtained from 259 (65%): Streptococcus pneumoniae 132 (51%), H. influenzae 22 (8.5%), salmonella spp 85 (32.8%), Neisseria meningitidis 9 (3.5%) and others 11 (4.2%). Over the surveillance period, there was a remarkable decline in the prevalence of H. influenza meningitis to only three cases or fewer per year compared with 42 in 2001. The minimum incidence of Streptococcus pneumoniae meningitis among children under 5 years of age was 33.7/100,000 of population and it was more prevalent during the dry season. The minimum incidence of non-typhoidal salmonella spp meningitis was 22.7/100,000, making it the second most common cause of paediatric bacterial meningitis with a case fatality rate of 18.2%. CONCLUSION: Hib conjugate vaccine delivered through the national immunisation programme is very effective in reducing Hib meningitis in children under 5 years of age. Continued laboratory-based surveillance of bacterial meningitis in Africa is needed to assess the effectiveness of vaccination programmes and detect other vaccine-preventable pathogens.