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.