[Seroepidemiological analysis of hepatitis B virus infection among adolescents aged 0-14 years in Henan Province and preliminary evaluation of the effectiveness of childhood hepatitis B vaccine immunization program].

Objective: To analyze the seroepidemiological characteristics of hepatitis B virus (HBV) infection among adolescents aged 0-14 years in Henan Province and to evaluate the effectiveness of the childhood hepatitis B vaccine (HepB) immunization program. Methods: From September 2021 to March 2022, a total of 4 883 adolescents aged 0-14 years were selected from 25 villages or communities of 18 provincial-level cities in Henan Province by using the multi-stage random cluster sampling method. Demographic data were collected through questionnaires. The 3 ml of blood samples were collected from individuals aged 0-4 years and 5 ml of blood samples were collected from individuals aged 5-14 years to test HBsAg, HBcAb and HBsAb. Data on vaccination were collected through Henan Provincial Immunization Information System and hepatitis B cases in Henan Province were collected through China Infectious Disease Reporting System. The effectiveness of the childhood HepB immunization program was analyzed. Results: The average age of 4 883 subjects was (7.32±2.81) years old. The positive rates of HBsAg and HBcAb were 0.1% (7/4 883) and 1.0% (50/4 883), and the population standardized rates were 0.3% and 1.7%. In 2002, the positive rate of HBsAg among adolescents aged 0-14 years in Henan Province was 3.39%. Compared with that in 2002, the number of chronic HBV infections among adolescents in Henan Province in 2022 decreased by about 0.7 million. In 2002, the vaccination rate of newborns who completed all three doses of vaccine was 6.26%. In 2003, the vaccination rate of the hepatitis B vaccine rose rapidly, reaching 90% in 2013 for the first time. After 2014, the vaccination rate in Henan Province continued to remain above 95%. The proportion of cases among children aged 1-4 years in clinical reports decreased from 0.43% (1 108/256 566) in 2006 to 0.01% (78/80 655) in 2021. The proportion of cases among adolescents aged 5-19 years decreased from 18.21% (46 710/256 566) in 2006 to 1.1% (827/80 655) in 2021. Conclusions: From 2002 to 2022, the positive rate of HBsAg among adolescents aged 0-14 years has decreased significantly in Henan Province. The effectiveness of the HepB immunization program for children is good.

[Analysis on the sequence mutation and evolution of HBV genome in China].

Objective: To understand immune escape mutation, drug resistance mutation, and genome evolution information of HBV genome sequence in China. Methods: The whole genome sequence information of HBV in China submitted in GenBank from 1998 to 2021 was selected as the object for analysis. MAFFT method was used for cluster analysis. Analysis of immune escape and drug-resistant mutations was performed using the online tool Gen2pheno. The BEAST 1.10.4 was used for analysis the time evolution of HBV sequences. Results: A total of 5 426 sequences were included in the dataset and distributed in 19 provinces of China. Type C accounted for the highest proportion (59.1%, 3 211/5 426), followed by type B (33.7%, 1 833/5 426). Immune escape mutations were found in 764 sequences (14.1%, 764/5 426). At least one reverse transcriptase region mutation occurred in 98.1% of the sequences. The evolutionary roots of most HBV sequences in China date from around 1801 AD. Conclusion: HBV-resistant mutation rate is high in China. HBV genomes evolve slowly.