Hospital-based Surveillance for Pediatric Bacterial Meningitis in the Era of the 13-Valent Pneumococcal Conjugate Vaccine in Ghana

Abstract

Background: Global surveillance for vaccine preventable invasive bacterial diseases has been set up by the World Health Organization to provide disease burden data to support decisions on introducing pneumococcal conjugate vaccine (PCV). We present data from 2010 to 2016 collected at the 2 sentinel sites in Ghana.

Methods: Data were collected from children <5 years of age presenting at the 2 major teaching hospitals with clinical signs of meningitis. Cerebrospinal fluid specimens were collected and tested first at the sentinel site laboratory with conventional microbiology methods and subsequently with molecular analysis, at the World Health Organization Regional Reference Laboratory housed at the Medical Research Council Unit The Gambia, for identification of Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis, the 3 most common bacteria causing meningitis.

Results: There were 4008 suspected cases of meningitis during the surveillance period, of which 31 (0.8%) were laboratory confirmed. Suspected meningitis cases decreased from 923 in 2010 to 219 in 2016. Of 3817 patients with available outcome data, 226 (5.9%) died. S. pneumoniae was the most common bacterial pathogen, accounting for 68.5% of confirmed cases (50 of 73). H. influenzae and N. meningitidis accounted for 6.8% (5 of 73) and 21.9% (16 of 73), respectively. The proportion of pneumococcal vaccine serotypes causing meningitis decreased from 81.3% (13 of 16) before the introduction of 13-valent PCV (2010-2012) to 40.0% (8 of 20) after its introduction (2013-2016).

Conclusions: Cases of suspected meningitis decreased among children <5 years of age between 2010 and 2016, with declines in the proportion of vaccine-type pneumococcal meningitis after the introduction of 13-valent PCV in Ghana.

Keywords: bacterial meningitis; pneumococcal conjugate vaccine.

Figure 1.

Quarterly distribution of suspected cases and deaths from 2010 through 2016.

Figure 2.

Flow chart of CSF sample processing. One isolate (Streptococcus pneumoniae) was not viable at the RRL. Of the CSF samples, 172 could not be linked to metadata from site. CSF cultures were done in 1611 cases, not done in 6, and the status was unknown in 2841. Between 2010 and 2013, culture-positive isolates and culture-negative CSF samples were sent to the RRL, and between 2014 and 2016, all CSF samples were sent to the RRL. Specimens were considered inconclusive if neither a pathogen nor the RNAse P gene was detected. Numbers of confirmed cases are displayed in red. Abbreviations: CSF, cerebrospinal fluid; PCR, polymerase chain reaction; RRL, Regional Reference Laboratory; WGS, whole-genome sequencing.

Figure 3.

Distribution of confirmed cases by year.

Figure 4.

Phylogenetic tree of pneumococcal isolates showing PCV era and antibiogram. Dashed blue line represents the reference genome. Six isolates from blood samples from Ghana included in the tree. Abbreviations: CHL, chloramphenicol; CTX, cotrimoxazole, ERY, erythromycin; OX, oxacillin; PCV, pneumococcal conjugate vaccine; TET, tetracycline.