Distribution Of Hepatitis B Virus Genotypes And Subgenotypes:A Meta-analysis

Background Hepatitis B virus(HBV)infection is a major global public health problem and can cause severe liver disease.With the further understanding about HBV,more and more attention have been paid to HBV genotypes and subgenotypes.HBV genotypes and subgenotypes have distinct geographical distributions and may be related to migration and lifestyles.The aim of this study was to investigate the distributions of HBV genotypes and subgenotypes and to uncover the association of HBV genotypes and clinical manifestation,disease progression,and response to antiviral therapy.The findings of this study can provide useful adjunctive information to predict the risk of liver-related morbidity and therapeutic efficacy in CHB patients.Methods A comprehensive literature search was performed in Pub Med and a systematic search of full-length HBV sequences and S gene sequences was conducted in the Gen Bank database.According to the included and exclusion criteria,classified genotypes by different countries and source,and then meta-analysis was applied to study the distribution of HBV genotypes.The relative evolution time of each genotype was estimated based on the HBV nucleotide mutation rate.Results In total,205 relevant studies from Pub Med,full-length gene data from 80 countries and S gene data from 85 countries were retrieved in this study.After inclusion and exclusion criteria,our study included 309 data from 110 countries,of which 35 countries had only one data and the other 75 countries had more than one data.A meta-analysis was performed for multi-data countries.Finally,this study obtained detailed HBV genotype data for 111 countries and subgenotypes of common genotypes in 61 countries.The distribution of genotypes is more detailed than those described by previous studies.While the overall genotype distribution is similar to that reported in previous studies,some notable aspects were different.The main genotypes present in south-eastern Africa,North Africa,and West Africa are genotypes A,D,and E,respectively.Genotypes G and H are mainly distributed in Mexico.Genotype F is mainly distributed in central and South America,but genotypes A and D are also common in Brazil,Cuba and Haiti.Subgenotypes A1 in Haiti and South Africa are less genetically distinct and are adjacent in the evolutionary tree.In Cuba,not far from Haiti,the most common subgenotype is A2,whose genetic sequence is phylogenetically related to the European A2.Conclusion In this study,an accurate distribution of HBV genotypes and subgenotypes was obtained by meta-analysis of 188 relevant studies data,full-length gene data from 58 countries and S gene data from 62 countries.The distribution of HBV genotypes and subgenotypes is different in different countries,which is related to human migration and ethnic integration.