The long-term persistence of hepatitis B surface antibody (anti-HBs) after hepatitis B vaccination among adults was not known clearly. This study aimed to assess the immunogenicity and persistence of antibodies 8 years after hepatitis B immunization with different vaccination schedules among adults who tested negative for hepatitis B surface antigen (HBsAg), anti-HBs, and hepatitis B core antibody (anti-HBc). A total of 771 participants who received the full vaccination course (three doses) and also had a blood sample taken 1 month after the first vaccination were recruited. Of these, 529 were excluded due to the missing data of anti-HBs 8 years after the first vaccination. Vaccinations were carried out at 0-1-3, 0-1-6 and 0-1-12 month vaccination schedules, and 104, 45, and 93 participants were included, respectively. The positive seroprotection rate was 85.9% 1 month after the third vaccination, and 58.3% 8 years later (χ 2 = 54.52, P < .001), while the geometric mean titer (GMT) of anti-HBs was 158.49 mIU/mL [95% confidence interval (CI): 131.83-190.55)] and 15.14 mIU/mL (95% CI: 10.96-20.42) after 1 month and 8 years, respectively. Compared with the standard 0-1-6 month vaccination schedule, the positive seroprotection rate and the GMT of the 0-1-3 month vaccination schedule had no difference. The longterm immune effect of the 0-1-3 month vaccination schedule was better than that of the 0-1-12 month vaccination schedule. No correlation was found between the GMT of anti-HBs 1 month and 8 years later.

y These authors equally contributed to this work. Keywords: Hepatitis B vaccine, immunization, adults, ChinaThe purpose of this study was to compare the response of hepatitis B vaccination with different vaccination schedules among seronegative adults, and to provide suitable vaccination schedules for floating and fixed population. The study included adults aged 20 to 39 y without prior history of vaccination with hepatitis B vaccine. The serum samples were collected and tested for hepatitis B surface antigen (HBsAg), hepatitis B surface antibody (anti-HBs), and hepatitis B core antibody (anti-HBc) levels. Out of all, 686 adults who were negative for anti-HBs, anti-HBc and HBsAg were vaccinated with 10 ug hepatitis B vaccine at 0, 1 and 3, 6 or 12 month schedules, and their antibody titers were monitored. The rates of completion of the vaccination in floating and fixed population were 90.4% and 94.1% respectively (p D 0.061). The anti-HBs positive rates in adults vaccinated at 0, 1 and 3 ,6 or12 month were 83.9%, 88.2% and 94.2% respectively (P D 0.0003). The corresponding geometric mean titers (GMTs) were 61.19 (95%CI:47.10-81.23) mIU/mL, 214.04(95%CI:157.14-291.61) mIU/mL and 345.78(95%CI:251.25-475.77) mIU/mL, respectively ( P < 0.0001). Vaccination of hepatitis B with both 0-1-6 and 0-1-12 month schedules in adults result in better level of immune responses. Also, a longer vaccination schedule (0-1-12 month) may be more suitable for floating population and 0-1-6 month schedule is recommended for the fixed population.

The aim of this study was to evaluate hepatitis B surface antibody (anti-HBs) levels one year after hepatitis B booster vaccination in anti-HBs-negative (<10 mIU/mL) children 11-15 y after primary vaccination. Anti-HBs titers were examined in 235 children who were negative for hepatitis B surface antigen (HBsAg), anti-HBs, and hepatitis B core antibody (anti-HBc). The children were then divided into 3 groups based on their anti-HBs levels pre-booster: Group I, <0 .1 mIU/mL; Group II, 0.1 to <1 .0 mIU/mL; and Group III, 1.0 to <10 .0 mIU/mL. They were vaccinated with 3 doses of hepatitis B vaccine (0-1-6 month, 20 ug), and anti-HBs levels were measured. One month after the first dose, the anti-HBs positive rates (≥ 10 mIU/mL) in Groups I-III were 56.14%, 83.61% and 100%. One month after the third dose, the anti-HBs-positive rates in Groups I-III were 96.49%, 98.36% and 100%. One year after the third dose, the anti-HBs-positive rates in Groups I-III were 73.68%, 75.41% and 98.29%, respectively. Protective levels declined more rapidly for those with lower titers. Children with pre-booster anti-HBs titers of 1-9.9 mIU/mL might not need any booster dose, and the children with pre-booster titers of 0.1-0.9 and <0 .1 mIU/mL might need more than one dose booster vaccination.

Wind barrier structures on railway bridges are installed to mitigate the wind effects on travelling trains; however, they cause additional wind loads and associated aerodynamic effects on the bridge. An innovative concept was developed for a wind barrier structure in this study that used a glass–fibre–reinforced polymer (GFRP) that may deform properly when subjected to a crosswind. Such deformation then allows for wind to pass, therefore reducing the wind loads transferred to the bridge. Wind tunnel experiments were conducted on a 1/40-scale train and bridge models with the proposed GFRP barrier subjected to airflow at different speeds up to 20 m/s. The side-force and overturning-moment coefficients of both the train and the bridge were evaluated to characterise the aerodynamic effects. The results show that favourable side-force and overturning-moment coefficients of the train were provided by wind barriers taller than 10 cm. The aerodynamic coefficients of the train were not significantly affected by the airflow speeds; meanwhile, the overturning-moment coefficient of the bridge decreased with the increase in airflow speed due to smaller wind resistance of the barrier after deformation. A numerical analysis was conducted on both the reduced- and full-scale models of the train–barrier–bridge system and the results supported the findings obtained from the wind tunnel experiments.

Immune responses of isolated anti-HBc subjects are not well characterized in populations in China. This study aimed to evaluate immune responses to hepatitis B vaccination in isolated anti-HBc positive subjects. A cohort of 608 subjects were selected and separated into isolated anti-HBc (negative for HBsAg and anti-HBs, positive for anti-HBc) and control (negative for HBsAg, anti-HBs, and anti-HBc) groups, who were matched by age and sex. All subjects received 3 doses of hepatitis B vaccine (20mg) at months 0, 1, and 3, followed by testing for serological responses 1 month after the third vaccination. The positive seroprotection rate and geometric mean titer (GMT) for hepatitis B surface antibody (anti-HBs) of isolated anti-HBc subjects were significantly lower than those in the control group(86.2% vs.92.1%, P D 0.02; 47.26 vs.97.81 mIU/mL, P < 0.001). When stratified by age, positive seroprotection rate in the isolated antiHBc group were 92%, 88.5% and 79.4% in the 20-34, 35-49, and 50-60 y old subgroups, respectively (x2 D 5.919, P D 0.04). Additionally, the GMT level for anti-HBs in the isolated anti-HBc group for different age subgroups were 104.43, 47.87 and 31.79 mIU/mL respectively (x2 D 19.44, P < 0.001). The GMT level for anti-HBc before vaccination were negatively correlated with GMT for anti-HBs after 3 doses of hepatitis B vaccine (r D ¡0.165, P < 0.001). In conclusion, isolated anti-HBc positive subjects can achieve good immune responses after hepatitis B vaccination, and the positive seroprotection rate and GMT level for anti-HBs were lower than the control group. Better responses could be observed in young adults, and significant negative correlations were found between GMT of anti-HBc before vaccination and GMT of anti-HBs after vaccination.