The residual risk of HBV infection was estimated by applying the refined infectious window-period estimate of 0.16 years (or 59 days)  to the derived incidence estimates. The residual risk of HBV infection among blood donations from the participating blood centers is shown in Table 8 . The estimated residual risks were 34.14, 25.85, 158.35, 44.48, 20.04 and 56.35 (per 100,000 person-years) in Hefei, Dalian, Changzhi, Kaifeng, Mianyang and Fujian, respectively. The residual risk of Dalian was the highest, approximately 6 times that of Fujian, which had the lowest residual risk.Table 8HBsAg Residual Risk by Blood Center/ Banks Among First-Time and Repeat DonorsBlood CenterFirst-timeRepeatWindow Periodsin YearOverall(per 105 py)Incidence(per 105 py)Residual risk(per 105 py)Incidence(per 105 py)Residual risk(per 105 py)Hefei315.3950.46 (6.13-182.04)45.257.24 (0.88-26.12)0.1634.14Dalian281.5245.04 (5.46-162.62)42.856.85 (0.83-24.75)0.1625.85Changzhi2347.34375.57 (64.40-721.85)338.2354.12 (9.28-104.01)0.16158.35Kaifeng372.8959.66 (7.22-215.38)84.5613.53 (1.64-48.84)0.1644.48Mianyang261.1441.78 (3.98-65.31)28.894.62 (0.44-7.22)0.1620.04Fujian640.19102.43 (12.39-369.78)41.196.59 (0.80-23.96)0.1656.35Average703.08112.49 (15.04-187.96)96.8315.49 (1.93-24.16)0.1656.53