Pneumococcal pneumonia and carriage in Africa before and after introduction of pneumococcal conjugate vaccines, 2000–2019: protocol for systematic review

Abstract

IntroductionAfrica harbours a high burden of pneumococcal disease, with associated high mortality rates. Despite 34 countries introducing the pneumococcal conjugate vaccine, which reduces the risk of pneumococcal carriage (a prerequisite for disease) of some of the most pathogenic pneumococcal serotypes, it remains uncertain whether they will achieve the sustained direct or indirect protection necessary to reduce pneumococcal carriage to levels sufficient to interrupt transmission and disease. We will therefore summarise the available data on the impact of the pneumococcal conjugate vaccine in reducing vaccine serotype carriage and pneumococcal pneumonia in Africa between 2000 and 2019.Methods and analysisUsing a predetermined search strategy, we will conduct a comprehensive search of PubMed, MEDLINE database, the Excerpta Medica Database, the ISI Web of Science (Science Citation Index), Scopus and the African Index Medicus to identify published studies reporting the prevalence of Streptococcus pneumoniae carriage (vaccine type and non-vaccine type), incidence rates of pneumococcal pneumonia and mortality among children, adults and HIV-infected (all-ages) pre-pneumococcal conjugate vaccine (PCV) and post-PCV introduction (published between 1st January 2000 and 31st December 2019) in African countries that have introduced PCVs (PCV7/PCV10/PCV13) in their routine national immunisation programme. The studies retained and data extracted will be assessed for bias using prevalidated tools and checklists. Heterogeneity across studies will be assessed using the χ2 test on Cochrane Q statistic. A random effect meta-analysis will be used to estimate the overall prevalence of pneumococcal carriage and incidence of pneumococcal pneumonia across studies with similar characteristics. Results will be reported in compliance with the Meta-Analysis Of Observational Studies in Epidemiology guidelines. The protocol has been prepared in accordance to the 2015 guidelines on Preferred Reporting Items for Systematic Reviews and Meta-Analyses.Ethics and disseminationThis systematic review will not require ethical approval as we will be using already published data. The final manuscript will be submitted for publication in a peer-reviewed journal and presented at conferences.PROSPERO registration numberCRD42019130976.

Impact of pneumococcal conjugate vaccine on the carriage density of Streptococcus pneumoniae and Staphylococcus aureus in children living with HIV: a nested case–control study

“…34 The impact of the introduction of PCV into childhood immunization programs on IPD and carriage in unvaccinated adults with HIV is an area of active investigation throughout sub-Saharan Africa. 35 Increased carriage density in the context of HIV could be due to a decrease in pneumococcus specific CD4-T lymphocytes, particularly the CD154 response, which is known to clear pneumococcus. 32,36 The impact of PCVs on the density of VT versus NVT serotypes is less clear.…”

The Streptococcus pneumoniae transcriptome in patient cerebrospinal fluid identifies novel virulence factors required for meningitis

“…Log 2 values for maximum and minimum gene transcript/million reads (TPM) abundance ranged from 1.00 to 15.68 (Supplemental data file 1). Of the 70 S. pneumoniae strains screened, the highest serotype alignments for an individual sample were serotypes 1 (n=4 samples) and 3 (n=3 samples), similar to the known distribution of serotypes causing meningitis in Malawi 26,27 . We further analysed each sample individually against the corresponding best-matched S. pneumoniae strain and used normalized gene expression to identify between 30 to 118 highly expressed genes per sample (Figure 1A, listed in Supplemental Table 4).…”

Pneumococcal Carriage and Antibiotic Resistance in Children Younger than 5 Years in Nouna District, Burkina Faso

“…17 Although vaccination may reduce pneumococcal carriage, expansion of non-vaccine serotypes may occur following vaccination, filling the niche of the vaccine serotypes and resulting in continued high rates of colonization. [34][35][36][37] There are several limitations to consider when interpreting these results. First, the sample size included was limited because of resource constraints, especially for community-level comparisons.…”