Surveillance of bacterial meningitis in an Angolan pediatric hospital after the introduction of pneumococcal conjugate vaccines

Background Bacterial meningitis (BM) is a significant cause of mortality in children; with deaths from BM in children aged <5 years in Angola estimated at 2395 in 2015. Streptococcus pneumoniae is one causative agent for BM in young children, and Angola introduced routine immunization with a 13-valent pneumococcal vaccine (PCV13) in 2012. This study assessed BM etiology in children in Angola following introduction of PCV13. Methods This was a prospective, observational, single-site study conducted from October 2016 to October 2017. Children aged 3 months–15 years were included. Suspected meningitis was defined according to the World Health Organization (WHO) guidelines. Detection and characterization of S. pneumoniae, Neisseria meningitidis, and Haemophilus influenzae was carried out using polymerase chain reaction (PCR) assay. Results A total of 1732 patients were enrolled and bacteria were detected in 137 cerebrospinal fluid samples. The most common pathogen detected was S. pneumoniae (43/137, 31.4%), followed by H. influenzae (21/137, 15.3%) and N. meningitidis (16/137, 11.7%) with 48% (10/ 21) of S. pneumoniae cases caused by PCV13 vaccine serotypes. N. meningitidis isolates were serogroups B, C and Y, and 67% (10/15) of H. influenzae isolates were type b. In patients with meningitis and a pathogen detected, mortality (38% (50/132) vs. 12% (101/ 818), P<0.0001) and severe neurological sequelae (15% (10/67) vs. 5% (35/667), P=0.002) were higher than in those without pathogens detected. Conclusions These data highlight that strategies to reduce the incidence of BM caused by N. meningitidis, S. pneumoniae and H. influenzae must continue to reduce mortality and morbidity.