In the four consecutive surveys conducted in 1994, 1999, 2004, and 2009, the prevalence of anti-HBc positivity, a surrogate marker of natural infection, increased gradually in the longitudinal follow-up of all birth cohorts, suggesting that exposure to HBV in the general population continued with age; however, HBsAg seropositivity did not increase among the cohorts [25], which suggests the long-term effectiveness in prevention against chronic HBV infection given that the risk of chronic HBV infection after exposure to HBV increases significantly with younger ages [26]. This evidence concerns the gene KRT88P and infection.