Objective: To evaluate repeated testing on blood screening platforms in confirmation of non-discriminatory reactive (NDR) samples in nucleic acid testing (NAT). Methods: A total of 102 HBsAg-negative/NAT NDR samples were collected from voluntary blood donors at Dalian Blood Center between January 2021 and December 2023. Repeated testing was performed using two NAT platforms (Cobas s201 and Panther). For the first round of repeated testing, all samples were tested 12 times on each system; for the second round, the samples which were non-reactive or only reactive once in the first round were tested an additional 8 times. Anti-HBc and anti-HBs was detected using electrochemiluminescence assay (ECA). Meanwhile, blood donors were followed up. Results: The proportion of anti-HBc+ in 102 NDR samples was 88.2%. Forty-one samples (40.2%, 41/102) and 7 samples were confirmed HBV DNA+ in first-round and second-round repeated testing, respectively. The cumulative confirmation rate of HBV DNA+ was 47.1% (48/102) after repeated testing. Extra five blood donors detected HBV DNA+ in follow-up were identified as anti-HBc+ occult hepatitis B virus infection (OBI), while no window period infection was observed. Ultimately, there were 53 HBV infected donors confirmed, 46 HBV infection-unconfirmed, and 3 HBV uninfected. No significant difference was observed between the confirmation rate of the first-round testing and the cumulative confirmation rate after the second-round testing (P>0.05). The proportion of anti-HBc+ donors was quite high in both HBV infection-confirmed (98.1%) and unconfirmed group (82.6%), and donors with seronegative and anti-HBs-only occupied a high proportion in the latter (P<0.05). Conclusion: Numerous repeated testing of NDR samples using NAT platforms cannot achieve complete confirmation of HBV infection. Supplementary anti-HBc testing can minimize potential OBI risk among NDR donors, and is low-cost and efficient.

Objective: To characterize the sequence polymorphism of HLA-A, -B, and -C loci in the northern Han Chinese population and to evaluate their selection signals and phylogenetic patterns based on long-read sequencing data. Methods: A total of 408 unrelated healthy blood donors were enrolled. Long-read sequencing of HLA-A, -B, and -C loci was performed using the PacBio Sequel II platform. The Ewens-Watterson neutrality test, sliding-window nucleotide diversity (π) and Tajima′s D analyses were conducted, together with genetic distance heatmaps, principal coordinates analysis (PCoA), and maximum likelihood phylogenetic analysis to assess polymorphism distribution, selection signals, and phylogenetic structure across the three loci. Results: The analyzed sequence lengths for the HLA-A, -B, and -C loci were 3 257 bp, 3 794 bp, and 3 831 bp, respectively; the numbers of locus-specific sequence types were 44, 82, and 56, with corresponding locus-specific sequence type diversities of 0.905 2, 0.964 9, and 0.939 8, respectively. The Ewens-Watterson test showed no significant deviation from neutrality (P>0.05). Sliding-window analysis revealed elevated π and Tajima′s D values in exons 2 and 3 as well as in certain intronic regions of HLA-A and HLA-B, whereas HLA-C exhibited relatively lower overall diversity. Genetic distance heatmaps, PCoA, and phylogenetic analysis consistently showed clear clustering in HLA-A and HLA-C, while HLA-B displayed the highest phylogenetic heterogeneity. Conclusion: HLA-A, -B, and -C gene sequences in the northern Chinese Han population exhibit high levels of polymorphism and marked regional heterogeneity. HLA-B shows greater diversity, stronger signals of selection, and more complex phylogenetic structure compared with HLA-A and HLA-C.

Objective: To investigate the impact of current laboratory testing models and screening strategies on blood safety by analyzing repeat nucleic acid testing (NAT) results obtained from blood donors who had dual-reactive enzyme-linked immunosorbent assay (ELISA) results but were initially nonreactive by NAT. Methods: Samples from blood donors with dual-reactive ELISA results and initially nonreactive NAT results collected at Dalian Blood Center from 2017 to 2025 were included. Repeated testing was performed using two NAT systems: transcription-mediated amplification (TMA) and polymerase chain reaction (PCR). The results were analyzed in terms of the frequency of reactive NAT results and the testing strategies, including minipool and individual donation testing. Results: A total of 199 samples with dual-reactive ELISA results and initially nonreactive NAT results were included，comprising 66 HBsAg-reactive samples，130 anti-HCV-reactive samples，and 3 HIV Ag/Ab-reactive samples. Among the HBsAg-reactive samples，57（57/66，86.4%）showed at least one reactive NAT result upon repeated testing，and 49 showed two or more repeat reactive results. Anti-HBc was reactive in 64 samples（64/66，97.0%）and nonreactive in 2 samples（2/66，3.0%）；both anti-HBc-nonreactive samples remained nonreactive in repeated NAT. No stable repeat nucleic acid reactivity was observed in anti-HCV- or HIV Ag/Abreactive samples. The TMA system detected 50 reactive samples（50/66，75.8%）through three combined assays plus one discriminatory assay, whereas the PCR system detected 51 reactive samples (51/66, 77.3%) through four rounds of individual-donation testing. Fortyfour samples were reactive on both systems, 6 were reactive only on the TMA system, and 7 were reactive only on the PCR system. Conclusion: Among blood donors with dual-reactive ELISA results and initially non-reactive NAT results, HBsAg-reactive samples contain a high proportion of low viral load HBV-related cases, with intermittent and probabilistic nucleic acid detectability. Both testing frequency and detection strategy significantly affect the detection of low viral load samples. These findings highlight the importance of recognizing the detection characteristics of low viral load HBV-related samples in order to optimize blood screening strategies and improve blood safety.

Objective: To analyze the epidemiological characteristics, associated factors, and vaccine effectiveness of two pertussis cluster outbreaks in two primary schools in Yangzhong City in 2025, so as to provide evidence for school based epidemic prevention and control. Methods: From August 26 to 30, 2025, a pertussis questionnaire was administered to the epidemic affected classes of two primary schools (school A and school B) in Yangzhong City. A descriptive epidemiological retrospective analysis was used to characterize the pertussis cluster outbreaks in Yangzhong City from March to July 2025. A 1∶5 matched case control study (79 cases, 395 controls) was performed. Multivariate Logistic regression was used to identify associated factors, and the clinical symptom incidence rates, types of pertussis containing vaccines, and timeliness of vaccination were compared between groups using Fisher s exact test. Results: From March to July 2025, a total of 79 pertussis cases were reported in the two schools, with attack rates of 1.33% and 1.01%, respectively. Cases were predominantly aged 7-8 years (85.37% in school A, 73.68% in school B), and the main clinical manifestation was productive cough (63.29%). The pneumonia incidence rate among hospitalized cases ( 57.14 %) was higher than that among nonhospitalized cases(4.17%)(Fisher s exact test, P <0.01). The interval from the last dose to onset was concentrated at 6 to <7 years (44 cases). Logistic regression showed that children exposed to secondhand smoke in daily life ( OR = 3.86 ), those whose desk mates or front/back desk mates took leave due to cough ( OR =4.67), and those whose dining table mates or front/back table mates took leave due to cough ( OR =3.67) had significantly higher risks of pertussis (all P <0.05). A high proportion of both the case group and the control group received the acellular DTaP vaccine (97.47% and 96.96%, respectively),while a low proportion received the pentavalent vaccine (1.27% and 3.04%, respectively). Additionally, one case received only three doses of the acellular DTaP vaccine.The difference in vaccine type distribution between the two groups was not statistically significant (Fisher s exact test, P =0.31). Conclusions The outbreaks represent breakthrough infections under high vaccine coverage. Close contact and secondhand smoke exposure are the main risk factors. A booster immunization strategy with diphtheria-tetanus-pertussis vaccine should be implemented for school aged children.

Objective To evaluate the disease risk of Vibrio parahaemolyticus (VP) in aquatic products of raw food in Guangzhou. Methods VP detection was carried out in aquatic products of raw food sold in Guangzhou from 2009 to 2022. Gene sequence and wgSNP analysis of 30 VP strains (including 15 food strains and 15 patient strains) were performed for the detection rate of pathogenic VP. sQMRA was applied to assess VP risk of aquatic products of raw food. Results The detection rate of VP in raw aquatic products in Guangzhou was 7.30% (98/1 343). The detection rate of TDH virulence gene in patient strains was 86.70% (13/15) , and the detection rate of TRH was 6.67% (1/15). In 15 food strains, TDH and TRH were negative. The WgSNP analysis showed that 2 food strains had high similarity with the patient strains, indicating the same cluster. Risk assessment showed that the number of Vibrio parahaemolyticus infection cases caused by intaking aquatic products of raw food in Guangzhou was 384 ever year. Conclusion The detection rate of VP in aquatic products of raw food is high in Guangzhou , and the detection rate of VP virulence genes in aquatic products of raw food is low. Gene sequence and wgSNP analysis can be used for risk assessment of food pathogenic bacteria. The risk of disease of Vibrio parahaemolyticus in aquatic products of raw food is high.

Objective: To establish a method for determining the molecular weight and molecular weight distribution of Poly(Lactide-co-Glycolide Acid) (PLGA) using Size Exclusion Chromatography-Refractive Index-Multiangle Laser Light Scattering (SEC-RI-MALLS) and Size Exclusion Chromatography-Refractive Index (SEC-RID), and to compare the results obtained from these two methods.
Methods: For SEC-RI-MALLS, tetrahydrofuran was used as the mobile phase, Shodex GPC KF-803L was employed as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, and an injection volume of 100 μL. For SEC-RID, tetrahydrofuran was also used as the mobile phase, Agilent PLgel 5 μm MIXD-D was used as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, differential detector temperature at 35 ℃, and an injection volume of 20 μL. The molecular weight and molecular weight distribution were calculated using Agilent’s GPC software. The newly established methods were validated methodologically, and the molecular weight and molecular weight distribution of 13 batches of samples were determined.
Results: The precision, accuracy, stability, and repeatability tests for SEC-RI-MALLS showed RSD values of 1.35%, 1.58%, 1.53%, and 1.26%, respectively. The SEC-RID method exhibited good linearity (r=0.999 9), with RSD values for precision, accuracy, stability, and repeatability tests (n=6) of 2.05%, 1.62%, 1.30%, and 2.97%, respectively. The results obtained from SEC-RI-MALLS were lower than those from SEC-RID, and the molecular weight distribution coefficient was smaller, but the results from the paired T-test performed with the value measured by SEC-RID method and the value measured by SEC-RI-MALLS method multiplied a conversion coefficient of 1.5 showed no significant difference between the two methods.
Conclusion: Both methods are stable and reliable, and can be used for the determination of PLGA molecular weight and molecular weight distribution based on the specific situations.

Objective:To evaluate the protective effectiveness (VE) of the acellular pertussis vaccine (aPV) against pertussis in children aged 2 months to 6 years.Methods:A test-negative case-control study was conducted among children aged 2 months to 6 years who sought medical care for cough and underwent pertussis nucleic acid testing at sentinel surveillance hospitals in Zhejiang Province in 2024. Cases were defined as those with positive pertussis nucleic acid test results, while controls were test-negative individuals matched 1∶1 based on propensity scores using the caliper matching method. Conditional logistic regression models were used to calculate odds ratios ( ORs) and VEs. Results:Among the 658 participants, 31.76% (209 cases) tested positive for pertussis. After propensity score matching, 203 cases and 203 controls were included in the analysis. The VE of 1-2, 3, and 4 doses of aPV against pertussis was 52.46% (95% CI:-39.82%-83.84%), 65.22% (95% CI: 6.86%-87.02%), and 72.21% (95% CI: 34.33%-88.24%), respectively. For pertussis-related hospitalization, the VE of 1-3 and 4 doses was 80.95% (95% CI:31.38%-94.71%) and 86.79% (95% CI: 51.89%-96.37%). The VE for those who completed 4 doses of vaccination and had intervals of less than 2 years, 2 years, 3 years, and 4 years or more after vaccination were 91.15% (95% CI: 67.61%-97.58%), 84.70% (95% CI: 43.71%-95.84%),56.23% (95% CI:-47.58%-87.02%), and 49.92% (95% CI:-83.74%-86.35%), respectively. Conclusion:The VE of aPV against pertussis in children aged 2 months to 6 years increases with the number of doses administered, and it is more effective in preventing hospitalization due to pertussis. The VE declines rapidly over time after the last dose. It is recommended to follow the new pertussis immunization program for timely and full vaccination.

Objective:To compare the dose-response effects of single-fraction ultra-high dose rate (FLASH) and conventional dose rate (CONV) whole abdominal irradiation (WAI) with X-rays on acute radiation-induced intestinal injury in mice, in order to identify optimal dose parameters and potential mechanisms.Methods:A total of 186 male C57BL/6J mice were randomly assigned to a non-irradiation group ( n=6), FLASH irradiation groups ( n=90), and CONV irradiation groups ( n=90). Acute radiation-induced intestinal injury models were established using single-fraction WAI with 11, 12, 13, 14, and 15 Gy X-rays (200 Gy/s for FLASH and 4 Gy/min for CONV). Changes in body weight, stool characteristics, and disease activity index (DAI) scores were assessed at 9 d post-irradiation. At 7 d post-irradiation at 11, 12, and 13 Gy, the intestines were collected for macroscopic examination and length measurement. The small intestine was selected for HE staining and quantitative analysis of intestinal crypt number and mucosal epithelial thickness. The survival of mice was assessed at 15 d post-WAI across all dose groups. Results:After single-fraction WAI at 11, 12, and 13 Gy, the body weight was higher in the FLASH group than that in the CONV group ( t=10.17, 12.65, 10.16, P<0.05). The DAI scores for the FLASH group were 1.00±1.10, 3.17±0.75, and 2.83±1.17, respectively, which were lower than those of the CONV group (4.33±0.52, 7.00±0.00, 8.60±0.55; t=8.70, 11.71, 14.99, P<0.05). However, after WAI at 14 Gy and 15 Gy, there were no significant differences in body weight and DAI between the FLASH group and the CONV group ( P>0.05). At 7 d after single-fraction WAI at 11, 12, and 13 Gy, mice in the FLASH group exhibited less intestinal congestion, edema, and shortening compared with the CONV group. The difference between the FLASH and CONV groups were statistically significant in small intestine length at 11 and 13 Gy ( t=4.42, 3.78, P<0.05), and in colorectal length at 11 and 12 Gy ( t=3.97, 3.12, P<0.05). Small intestine HE staining revealed superior preservation of intestinal architecture in the FLASH group compared with the CONV group, characterized by longer villi, increased crypt numbers, thicker mucosal epithelium, and enhanced structural integrity. The differences in crypt number and mucosal epithelial thickness were statistically significant ( tcrypt=13.10, 23.80, 11.90; tmucosal=5.75, 2.64, 7.74; P<0.05). At 15 d post-irradiation, the survival rate in the 15 Gy FLASH group was higher than that in the CONV group (50% vs. 10%, χ2=5.39, P<0.05), with a median survival extension of 6 d ( HR=0.340, 95% CI: 0.115 4-0.999 9). No significant survival differences were observed between the FLASH group and the CONV group at 11, 12, 13, and 14 Gy ( P>0.05). Conclusions:FLASH irradiation significantly alleviated acute radiation-induced intestinal injury from medium single-fraction WAI with 11, 12, and 13 Gy X-rays compared with CONV irradiation, and showed potential to improve mouse survival after single-fraction WAI at 15 Gy. This effect is likely associated with the preservation of intestinal crypts and exhibits a dose-dependent relationship.

The morbidity and mortality associated with diphtheria have been effectively managed through mass immunization strategies. Nevertheless, recent outbreaks of diphtheria have been reported in various regions of Africa and Asia. In addition to infections among children, there has been a notable increase in cases among middle-aged and elderly individuals, underscoring the necessity of continued vigilance in the control of diphtheria. This paper reviewed the epidemiology of diphtheria, the current application of vaccines, and immunization strategies, with the aim of providing evidence for the prevention and control of this disease.

Objective To investigate the predictive value of early fluid balance combined with daily average fluid intake on the prognosis of patients who received hematoma evacuation for spontaneous intracerebral hemorrhage(sICH).Methods This study retrospectively and consecutively enrolled patients who underwent hematoma evacuation for sICH admitted to the Neurosurgical Intensive Care Unit of North China University of Science and Technology Affiliated Hospital between January 2023 and January 2025.Patients'baseline and clinical data were collected,including gender,age,admission vital signs(body temperature,respiratory rate,heart rate,systolic and diastolic blood pressure),medical history(hypertension,diabetes mellitus,coronary heart disease),admission Glasgow coma scale(GCS)score,admission laboratory parameters(including white blood cell count,red blood cell count,platelet count,urine bacterial levels,urine ketones,urine pH,homocysteine),hemorrhage location,hemorrhage volume,time from ictus to surgery,and hematoma evacuation rate(hematoma evacuation rate[％]=[preoperative hematoma volume-postoperative hematoma volume]/preoperative hematoma volume × 100％).Fluid intake,output,balance,daily average intake,and cumulative fluid balance during the early postoperative period(the first to seventh 24-hour periods)were assessed and recorded.Fluid intake comprised the sum of intravenously administered fluids(crystalloids,hypertonic fluids,colloids,blood products,and parenteral nutrition),enteral nutrition(nasogastric feeding solutions and water),and renal replacement therapy fluids.Fluid output comprised the sum of urine volume,vomitus,drainage fluid,and dialysis fluid losses.Fluid balance was defined as the difference between fluid intake and output.Daily average intake was calculated as the average of the fluid intake over the first seven postoperative 24-hour periods.Cumulative fluid balance was the sum of the fluid balances over the first seven postoperative 24-hour periods.Patient outcomes were assessed at 30 days postoperatively.Discharged patients underwent outpatient review or telephone follow-up,while inpatients were evaluated by neurosurgeons.Prognosis was evaluated using the 30-day modified Rankin scale(mRS)score:mRS scores 0-3 were classified as favorable prognosis,and mRS scores 4-6 as poor prognosis.Patients were subsequently divided into favorable prognosis and poor prognosis groups based on mRS scores.Factors with P＜0.05 in univariate comparisons and without collinearity(multicollinearity was defined by:tolerance＜0.1 and variance inflation factor＞10)were included in multivariate Logistic regression analysis to identify independent risk factors for poor 30-day prognosis after hematoma evacuation in sICH patients.Receiver operating characteristic(ROC)curve analysis was employed to evaluate the predictive value of relevant factors for poor 30-day prognosis after hematoma evacuation in sICH patients.Results A total of 320 patients who underwent hematoma evacuation for sICH were enrolled,including 192 males and 128 females,with an age range of 20-91 years(median age 62[53,68]years).Among them,144 patients were assigned to the favorable prognosis group and 176 to the poor prognosis group.The poor prognosis group exhibited significantly higher hemorrhage volume,homocysteine level,fluid intake at the 3rd,5th,6th,and 7th 24-hour periods,fluid balance at the 3rd,5th,6th,and 7th 24-hour periods,daily average intake,and cumulative fluid balance compared to the favorable prognosis group(all P＜0.05).The favorable prognosis group had a significantly higher hematoma evacuation rate,GCS score,proportion of supratentorial hemorrhage and negative urine ketones than the poor prognosis group(all P＜0.05).No significant differences were found in other clinical data(all P＞0.05).Fluid balance over the first seven postoperative 24-hour periods displayed a rise-decline-rise pattern in the poor prognosis group and a rise-decline pattern in the favorable prognosis group.Both groups peaked at the 3rd 24-hour period.Multivariate Logistic regression analysis identified fluid balance at the 3rd 24-hour period(OR,2.013,95％CI 1.386-2.922,P＜0.01)and daily average intake(OR,3.583,95％CI 1.793-7.161,P＜0.01)as independent influencing factors for poor 30-day prognosis after hematoma evacuation in sICH patients.ROC curve analysis revealed that the area under the curve(AUC)for fluid balance at the 3rd 24-hour period and daily average intake in predicting poor 30-day prognosis were 0.699(95％CI 0.642-0.757)and 0.765(95％CI 0.712-0.819),respectively.The combined model of fluid balance at the 3rd 24-hour period and daily average intake achieved an AUC of 0.804(95％CI 0.756-0.853),demonstrating significantly superior predictive performance compared to either variable alone(both P＜0.05).Conclusions The combination of fluid balance at the 3rd 24-hour period and daily average intake demonstrates modest predictive value for poor 30-day prognosis after hematoma evacuation in sICH patients.These findings require validation through multicenter,large-scale,prospective studies.