TT-HBV can still occur after transfusion, even though the carrier blood has tested negative for HBsAg. Apart from occult HBV infections, there remains a limitation in the model that was used to estimate the residual risk of HBV, because neither the window period nor the incidence of donor HBV infections is precisely known. Thus, theoretically, the actual infection risk may be underestimated, which might not accurately reflect infectivity. However, the estimated result of Li’s model can still be used to evaluate the safety of blood supplies.