Mapping hepatitis B virus genotypes on the African continent from 1997 to 2021: a systematic review with meta-analysis

Hepatitis B virus (HBV) has ten genotypes (A–J) and over 40 sub-genotypes based on the divergence of ≥ 8% and 4 to < 8% in the complete genome respectively. These genotypes and sub-genotypes influence the disease prognosis, response to therapy and route of viral transmission. Besides, infection with mixed genotypes and recombinant genotypes has also been reported. This study aimed at mapping the de novo genotypes and correlate them with the immigration trends in order to inform future research on the underlying reasons for the relative distribution of HBV genotypes from a large sample size pooled from many primary studies. Data was extracted from 59 full research articles obtained from Scopus, PubMed, EMBASE, Willy library, African Journal Online (AJOL) and Google Scholar. Studies that investigated the genotypes, sub-genotypes, mixed genotypes and recombinant were included. The Z-test and regression were used for the analysis. The study protocol is registered with PROSPERO under the registration number CRD42022300220. Overall, genotype E had the highest pooled prevalence significantly higher than all the other genotypes (P < 0.001). By region, genotype A posted the highest pooled prevalence in eastern and southern Africa, E in west Africa and D in north Africa (P < 0.0001). Regarding the emerging genotypes B and C on the African continent, genotype B was significantly higher in south Africa than C (P < 0.001). In contrast, genotype C was significantly higher in east Africa than west Africa (P < 0.0001). The A1 and D/E were the most diverse sub-genotypes and genotype mixtures respectively. Finally, we observed a general progressive decrease in the prevalence of predominant genotypes but a progressive increase in the less dominant by region. Historical and recent continental and intercontinental migrations can provide a plausible explanation for the HBV genotype distribution pattern on the African continent.