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Background: The rapid spread of HBV has resulted in the emergence of new variants. These viral genotypes and variants, in addition to carcinogenic risk, can be key predictors of therapy response and outcomes. As a result, a better knowledge of these emerging HBV traits will aid in the development of a treatment for HBV infection. However, many Sub-Saharan African nations, including Kenya, have insufficient molecular data on HBV strains circulating locally. This study conducted a population-genetics analysis to evaluate the genetic diversity of HBV among Kenyan blood donors. In addition, within the same cohort, the incidence and features of immune-associated escape mutations and stop-codons in Hepatitis B surface antigen (HBsAg) were determined., Methods: In September 2015 to October 2016, 194 serum samples were obtained from HBsAg-positive blood donors residing in eleven different Kenyan counties: Kisumu, Machakos, Uasin Gishu, Nairobi, Nakuru, Embu, Garissa, Kisii, Mombasa, Nyeri, and Turkana. For the HBV surface (S) gene, HBV DNA was isolated, amplified, and sequenced. The sequences obtained were utilized to investigate the genetic and haplotype diversity within the S genes., Results: Among the blood donors, 74.74% were male, and the overall mean age was 25.36 years. HBV genotype A1 (88.14%) was the most common, followed by genotype D (10.82%), genotype C (0.52%), and HBV genotype E (0.52%). The phylogenetic analysis revealed twelve major clades, with cluster III comprising solely of 68 blood donor isolates (68/194-35.05%). A high haplotype diversity (Hd = 0.94) and low nucleotide diversity (π = 0.02) were observed. Kisumu county had high number of haplotypes (22), but low haplotype (gene) diversity (Hd = 0.90). Generally, a total of 90 haplotypes with some consisting of more than one sequence were observed. The gene exhibited negative values for Tajima's D (-2.04, p<0.05) and Fu's Fs (-88.84). Several mutations were found in 139 isolates, either within or outside the Major Hydrophilic Area (MHR). There were 29 mutations found, with 37.9% of them situated inside the "a" determinant. The most common mutations in this research were T143M and K122R. Escape mutations linked to diagnostic failure, vaccination and immunoglobulin treatment evasion were also discovered. Also, one stop-codon, W163STP, inside the MHR, was found in one sample from genotype A., Conclusion: In Kenya, HBV/A1 is still the most common genotype. Despite limited genetic and nucleotide diversity, haplotype network analysis revealed haplotype variance among HBV genotypes from Kenyan blood donors. The virological properties of immune escape, which may be the source of viral replication endurance, were discovered in the viral strains studied and included immune-escape mutations and stop-codon. The discovery of HBsAg mutations in MHR in all isolates highlighted the need of monitoring MHR mutations in Kenya., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2023 Langat et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

BackgroundChronic Hepatitis B virus (HBV) infection causes liver cirrhosis and cancer and is a major public health concern in Kenya. However, so far no systematic review and meta-analysis has been conducted to estimate the burden of disease in the country. A better understanding of HBV infection prevalence will help the government implement efficient strategies at eliminating the disease. This systematic review and meta-analysis was therefore conducted to summarize and update the available information on the burden of HBV in Kenya.MethodWe systematically searched PubMed, Science Direct, Web of Science, Scopus, African Journals OnLine, and Google Scholar databases to retrieve primary studies conducted between January 1990 and June 2021 that assessed the prevalence of HBV infection in Kenya based on measurement of the Hepatitis B Surface Antigen (HBsAg). Meta-analysis was performed using the random effects model where HBsAg prevalence was estimated at a 95% confidence interval (CI) after simple pooling analysis. Potential sources of heterogeneity were also investigated.ResultsFifty studies were included in the meta-analysis with a sample size of 108448. The overall pooled prevalence estimate of HBV in Kenya was 7.8% (95% CI: 5.8–10.1). Subgroup analysis revealed the highest prevalence among patients presenting with jaundice at 41.7% (95% CI: 13.5–73.3) whereas blood donors had the lowest prevalence at 4.1% (95% CI: 2.4–6.3). Prevalence in Human Immunodeficiency Virus (HIV)-infected individuals was 8.2% (95% CI: 5.8–11.0). An estimate of the total variation between studies revealed substantial heterogeneity (I2 = 99%) which could be explained by the study type, the risk status of individuals, and the region of study.ConclusionWe present the first systematic review and meta-analysis of the prevalence of HBV in Kenya. Our results show that the burden of HBV in Kenya is still enormous. This calls for an urgent need to implement public health intervention measures and strategic policies that will bring the disease under control and lead to final elimination.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?RecordID=264859, identifier: CRD42021264859.