Objective: To explore the impact of different blood donation scenarios on population characteristics and blood donation behaviors, and to provide a basis for precise blood donation recruitment. Methods: Eligible voluntary blood donors with complete records from four scenarios in Xi'an: medical institutions, cultural tourism SITES, commercial superstores, and blood centers. After a preliminary analysis of overall donor characteristics across the four scenarios, three core subgroups were defined based on scenarios and donor population differences: the medical subgroup (aged 30-39 years), the blood center subgroup (aged 30-39 years), and the cultural tourism and commercial superstore subgroup (aged 18-29 years). Baseline characteristics, blood donation behaviors, and blood test results were compared among the subgroups. Results: The blood donors in all four scenarios were mainly male, but the proportion of female donors in the medical scenario was the highest (26.4%, 8 878/33 634). In terms of age distribution, the cultural tourism and commercial superstore scenarios were dominated by donors aged 18-29, while the blood center and medical scenarios were dominated by those aged 30-39, with the highest proportion of donors over 40 in the medical scenario. The occupational and educational composition of blood donors in the blood center scenario spanned a wide range, exhibiting a clear bipolar distribution. Significant differences were observed in baseline characteristics, blood donation behaviors, and blood test results among the three core subgroups (P<0.001). The medical subgroup was mainly composed of enterprise/industrial workers and married individuals, with high proportions of first-time blood donors, and the highest unqualified rate of infectious indicators (2.0%, 274/13 509). The cultural tourism and commercial superstore subgroup was mainly unmarried and students, featured high proportions of large-volume donations and evening donations, and had a relatively high unqualified rate for ALT (0.4%, 130/31 443). The blood center subgroup had a complex population structure, a high proportion of repeat blood donors (45.3%, 6449/14 225), and moderate results in all test indicators. Conclusion: There is an inherent correlation between the attributes of blood donation scenarios, population characteristics, and blood donation behaviors. The differences among the three core subgroups provide a clear basis for precise scenario operation. By constructing transformation channels between different scenarios and optimizing scenario-specific strategies, the structure of blood donors can be improved, thereby supporting the sustainable development of voluntary blood donation.

Objective:To analyze the human immunodeficiency virus (HIV) screening status and the resulting residual risk (RR) among blood donors across 17 provincial blood centers in China.Methods:This study used a cross-sectional study. Data on HIV infection markers per 100 000 first-time donors (FD) and repeat donors (RD) from January 2015 to December 2024 were extracted from the National Blood Establishment Performance Comparison Information Management System. Questionnaires were used to collect each center′s HIV screening strategy, algorithm, serological test (ST) kit manufacturers, gray-zone setting for ST, and nucleic acid test (NAT) modality, method, and platform. The incidence-window-period model was used to calculate the residual risk for first-time donors (RR FD), repeat donors (RR RD), and total donors (RR TD) at each center. Horizontal and vertical analysis of RR FD, RR RD, and RR TD across centers and years were performed. Results:All 17 centers applied the same HIV screening strategy which was two rounds of ST followed by one round of NAT. Eight of them operated a single screening algorithm, six employed two algorithms and three used three. Eleven centers used both imported and domestic ST kits, five relied on domestic ST kits only, and one used imported ST kits only, while four centers never set a grey zone for ST throughout the decade. For NAT modalities, eight centers adopted both individual nucleic acid test (ID-NAT) and minipool nucleic acid test (MP-NAT), eight used MP-NAT only and one used ID-NAT only. Seven centers combined transcription mediated amplification (TMA) and polymerase chain reaction (PCR), nine used PCR only and one used TMA only, and fourteen centers ran both imported and domestic NAT systems, two used imported systems only and one used a domestic system only. Over the ten-year period, the mean RR FD across the centers ranged from 2.22 to 12.33 per 10 6 person-years, RR RD from 0.83 to 3.29 per 10 6 person-years and RR TD from 1.59 to 9.29 per 10 6 person-years, with center Z4 consistently showing the lowest values for all three metrics and center U4 recording the highest RR FD and RR TD, while center D2 had the highest RR RD. In 2024 compared with 2015, eleven centers achieved a lower RR FD and ten centers achieved lower RR RD and RR TD. The RR FD and RR TD of centers W2 and U4 displayed pronounced fluctuations and an upward trend in recent years. Conclusions:The 17 provincial blood centers maintain consistent HIV screening strategies, while demonstrating variations in screening algorithm, ST kit manufacturers, NAT modalities, methods, and platform. And the RR FD, RR RD, and RR TD differ across centers. Although most centers show declining trend in RR over the ten-year period, some centers exhibite data fluctuations with a rising trend, suggesting potential for further optimization of HIV screening protocols.

Objective:To analyze the human immunodeficiency virus (HIV) screening status and the resulting residual risk (RR) among blood donors across 17 provincial blood centers in China.Methods:This study used a cross-sectional study. Data on HIV infection markers per 100 000 first-time donors (FD) and repeat donors (RD) from January 2015 to December 2024 were extracted from the National Blood Establishment Performance Comparison Information Management System. Questionnaires were used to collect each center′s HIV screening strategy, algorithm, serological test (ST) kit manufacturers, gray-zone setting for ST, and nucleic acid test (NAT) modality, method, and platform. The incidence-window-period model was used to calculate the residual risk for first-time donors (RR FD), repeat donors (RR RD), and total donors (RR TD) at each center. Horizontal and vertical analysis of RR FD, RR RD, and RR TD across centers and years were performed. Results:All 17 centers applied the same HIV screening strategy which was two rounds of ST followed by one round of NAT. Eight of them operated a single screening algorithm, six employed two algorithms and three used three. Eleven centers used both imported and domestic ST kits, five relied on domestic ST kits only, and one used imported ST kits only, while four centers never set a grey zone for ST throughout the decade. For NAT modalities, eight centers adopted both individual nucleic acid test (ID-NAT) and minipool nucleic acid test (MP-NAT), eight used MP-NAT only and one used ID-NAT only. Seven centers combined transcription mediated amplification (TMA) and polymerase chain reaction (PCR), nine used PCR only and one used TMA only, and fourteen centers ran both imported and domestic NAT systems, two used imported systems only and one used a domestic system only. Over the ten-year period, the mean RR FD across the centers ranged from 2.22 to 12.33 per 10 6 person-years, RR RD from 0.83 to 3.29 per 10 6 person-years and RR TD from 1.59 to 9.29 per 10 6 person-years, with center Z4 consistently showing the lowest values for all three metrics and center U4 recording the highest RR FD and RR TD, while center D2 had the highest RR RD. In 2024 compared with 2015, eleven centers achieved a lower RR FD and ten centers achieved lower RR RD and RR TD. The RR FD and RR TD of centers W2 and U4 displayed pronounced fluctuations and an upward trend in recent years. Conclusions:The 17 provincial blood centers maintain consistent HIV screening strategies, while demonstrating variations in screening algorithm, ST kit manufacturers, NAT modalities, methods, and platform. And the RR FD, RR RD, and RR TD differ across centers. Although most centers show declining trend in RR over the ten-year period, some centers exhibite data fluctuations with a rising trend, suggesting potential for further optimization of HIV screening protocols.

Objective:To analyze the mutation of T-cell and B-cell epitopes derived from HBV PreS-S protein in occult hepatitis B virus (OHBV) and investigate the biological mechanisms of occult hepatitis B virus infection (OBI) and HBsAb positive OBI.Methods:The PreS-S region of OBI samples were amplified by nested PCR, the products were sequenced and HBV genotypes were determined. The mutations of T-cell and B-cell epitopes derived from HBV PreS-S protein were analyzed and compared among groups of HBV genotypes and the presence of HBsAb. The affinity of the high frequency of T-cell epitope substitutions were analyzed by SYF PEITHI, the changes of antigenic characteristics of high frequency of B-cell epitope substitutions were analyzed by Ab Designer, Expasy ProtParam tool, Epitope Prediction and Analysis Tools.Results:The PreS-S region of HBV was amplified in 21 samples, including 4 HBsAb+ OBI B, 6 HBsAb-OBI B, 6 HBsAb+ OBI C, 5 HBsAb-OBI C. The mutation rates in PreS-S region of OBI were significantly higher than wild type HBV strains(OBI Bvs. WT B: 2.64%: 0.66%, P<0.001; OBI Cvs. WT C: 3.67%: 1.19%, P<0.001). The mutation rates of the immunoreactive area were significantly higher than non-immunoreactive area in OBI (OBI B: 3.57%: 1.86%, P=0.005; OBI C: 4.78%: 2.65%, P<0.001). The mutation rates of the immunoreactive and non-immunoreactive area in OBI C were higher than OBI B, but there was no statistically significant difference (immunoreactive area: 4.78%: 3.57%, P=0.107; non-immunoreactive area: 2.65%: 1.86%, P=0.142). The mutation rates of T-cell and B-cell epitopes of HBsAb-OBI were higher than HBsAb+ OBI, although there was no significant difference (HBsAb-OBI Bvs. HBsAb+ OBI B: 4.17∶3.01, P=0.303; HBsAb-OBI Cvs. HBsAb+ OBI C: 5.65∶4.26, P=0.207). The affinity analysis of 4 high frequency T-cell epitope substitutions, including T47A/K, S174N, L175S, V177A, showed that the changes of affinity of most mutation sites were not obvious; the antigenicity analysis of 3 high frequency B-cell epitope substitutions, including G73S, K122R, I126M/T, did not show noticeable changes and the hydrophilicity, surface accessibility of some mutation sites were even better than wild strain. Conclusions:The mutation rates in PreS-S region of OBI were significantly higher than wild type HBV strains. The mutation rates of the immunoreactive area were higher than non-immunoreactive area in OBI. The variant activity of OBI C was higher than OBI B. The mutations of OBI might occur randomly and were not selected by antibody pressure. Single epitope and multi-epitopes combinational mutations might be a reason for OBI.

Objective To analyze the mutation of PreS-S region in occult hepatitis B virus(OHBV) in HBV infected persons with positive HBsAb and investigate the biological mechanisms of the special infectious model.Methods A total of 38 HB-sAb positive OBI serum samples were amplified by Nested PCR and sequenced,HBV genotype and serotype were determined.The amino acid sequences of OHBV were compared to the corresponding sequence of wild-type strains of similar genotype obtained from the GenBank database.Results PreS-S segment of 11 samples were obtained and 8 samples were sequenced successfully.Among which,5 were genotype C and 3 were genotype B.Genotype B were all serotype adw,while genotype C were 1 adw and 4 adr.The mutation rates of PreS-S region,the immunoreactive area and the major hydrophilic region (MHR) were higher in OHBV than the wild-type strains (2.6％ vs 0.8％,x2 =40.23,3.2％ vs 0.3％,x2 =52.13,3.6％ vs 0.6％,x2 =13.25,all P＜0.01) and the substitutions of I126T,Q129R,M133T,F134I,D144E,G145K in α determinant were found in OBI samples.The mutation rate of amino acids in PreS-S region was higher in genotype C than genotype B (3.5％ vs 1.2％,x2--15.98,P＜0.01),meanwhile,the mutation rates in MHR,α determinant and immunoreactive region were higher in genotype C too,but no statistical significance was attained (4.7％ vs 1.7 ％,x2 =2.96,3.6 ％ vs 2.9％,x2 =0.25,4.1％ vs 2.3％,x2 =3.59,all P ＞0.05).Conclusion Mutations in PreS-S region,especially in immunoepitope,might change the virus'immunogenicity leading to escape from immune response and cause OBI with HBsAb positive.