Objective: To analyze serological and molecular characteristics of asymptomatic HBV infection in HBV surface antigen positive (HBsAg+) blood donors from Dalian. Methods: The prevalence of HBsAg was analyzed among blood donors in Dalian between 2013 and 2022. Randomly selected HBsAg+ blood samples were subjected to HBV serological testing, HBV viral DNA quantification, and HBV genotyping. Results: Over this ten-year period, the prevalence of HBsAg decreased from 1.25% to 0.50% among blood donors in Dalian. Donors who tested positive for HBsAg prior to donation using a rapid test (RT) accounted for 92.5% of all HBsAg+ donors identified. A total of 240 confirmed HBsAg+ blood donors were randomly selected, including 125 donors with positive results and 115 with negative results in the pre-donation rapid test. HBsAg+ donors were mainly males (71.2%), with a median age of 42, and 97.5% of them being first-time donors. Based on HBV serological profiles, three stages of infection were identified: early infection (2.9%), suspected acute hepatitis (0.8%), and chronic infection (96.3%). The dominant HBV genotypes were C (68.9%) and B (28.4%). Among chronic HBV infection individuals, donors infected with HBV genotype B were older than those infected with genotype C (median age: 45y vs 38.5y, P<0.05). Additionally, they showed significantly lower HBsAg levels with a narrower distribution range than those infected with genotype C [median: 23.2 IU/mL (range: <0.05-7 910 IU/mL) vs 968 IU/mL (range: <0.05-3.4×10 ), P<0.05]. However, no significant difference was observed in the HBV DNA loads between these two genotypes (P>0.05). Conclusion: Between 2013 and 2022, the prevalence of HBsAg among blood donors in Dalian showed a year-over-year decline. Chronic infection was predominant among HBsAg+ first-time blood donors. The characteristics of chronic infection in blood donors differed significantly depending on the viral genotype, manifesting as differences in age of infected individuals and HBsAg level distribution.

【Objective】 To investigate the serological and molecular characteristics of HBsAg+ /HBV DNA non-reactive (NR) infections. 【Methods】 Samples tested as HBsAg+ and HBV DNA NR were confirmed by individual NAT repeat testing, viral particle concentration by PEG precipitation combined with in-house nested PCR and real-time quantitative PCR, anti-HBc testing, and HBsAg quantification. HBV sequences were compared with those from donors with chronic and occult infection as controls. 【Results】 A total of 792 195 samples were screened between January 2011 and December 2020, of which 53 (1: 14 947) were confirmed HBsAg+ /HBV DNA NR. HBV DNA was detected further in five (9.4%) samples; three S sequences and four Pre Core/Core sequences were obtained. Unique amino acid substitutions (P130T, P135Q/S, R151Q, G153S and S155F) were found in the Core protein that may affect virus packaging and replication. 【Conclusion】 Extremely low HBV DNA level was detected in plasmas of HBsAg+ /HBV DNA NR donors. Barely detectable HBV DNA might be associated with unusual mutations in the Pre Core/Core protein affecting viral replication. More sensitive HBV DNA and/or HBsAg assays may be considered to further reduce the potential HBV transfusion-transmission residual risk.

【Objective】 To investigate HIV-1 subtype distribution and trend among Dalian blood donors between 2011 and 2020, in order to provide information to improve blood safety and HIV prevention. 【Methods】 HIV RNA was purified from plasma samples of Dalian blood donors with confirmed HIV infection, which were collected between 2011 and 2020. The HIV pol gene was amplified and sequenced. HIV-1 subtypes were determined by phylogenetic analysis. 【Results】 HIV RNA was successfully genotyped in 174 samples from HIV-infected donors. The main subtypes among Dalian blood donors were CRF01_AE(69.5%), CRF07_BC(17.2%), B(5.2%), CRF02_AG(2.9%), C(1.1%), CRF55_01B(1.1%), CRF08_BC(0.6%), CRF59_01B(0.6%) and CRF79_0107(0.6%). There were still 2 cases (1.1%) unclassified. Significant difference was observed when comparing with the published national data. The prevalence of CRF01_AE strains decreased over the years, while CRF07_BC increased significantly. CRF02_AG carriers differed from donors infected with other HIV subtypes by being mostly females (40.0% vs. 2.4%), aged (median: 35y vs. 26y) and lower educational background(junior school degree or below). And 96.7% of local CRF01_AE cases were related to HIV strains, which were reported to circulate in Northeast China and in the MSM population. 【Conclusion】 HIV-1 among Dalian blood donors had unique molecular epidemiology and the trends of 07_BC increasing and 01_AE decreasing lagged behind the overall national data. Donor education on blood safety and consultation services to high risk group before donation still need improvement.