PI-CHUAN FANMEI-HWEI CHANGPING-ING LEESafary A.Lee C.-Y.2020-12-212020-12-2119980264-410Xhttps://www.scopus.com/inward/record.uri?eid=2-s2.0-0031986247&doi=10.1016%2fS0264-410X%2897%2900179-5&partnerID=40&md5=ea861b0d4e0f4f3f47aa8e0fe42a075dhttps://scholars.lib.ntu.edu.tw/handle/123456789/529237Long-term persistence of hepatitis A virus (HAV) serum antibody in vaccinated children has not been demonstrated in previous studies. To study the long-term immunogenicity to HAV vaccine, three doses of strain HM 175 HAV vaccine with 360 enzyme-linked immunosorbent assay units were administered to 107 children, aged from 1.0 to 6.8 years, at 0, 1 and 6 months. The administration of one vaccine dose induced seropositivity (anti-HAV titer ? 20 mIU ml-1) in 95% of all vaccinees at month 1. All subjects remained seropositive until month 6. The titers of HAV antibody remained above 20 mIU ml-1 in all subjects followed up to 60 months. The geometric mean titer (GMT) reached its peak (3802 mIU ml-1) at month 7, i.e. 1 month after the booster dose, and then declined until the end of follow-up at month 60 (661 mIU ml-1). A trend of higher GMT in female subjects persisted up to month 60. The changes of the GMT over time were best described by the regression equation: log (GMT) = 3.26 - 0.08 x (age in years) (r = -0.95, P = 0.014). According to this equation, the geometric mean concentration would reach 20 mIU ml-1 at around 24.5 years after the beginning of vaccination. In conclusion, those who completed the recommended three-dose inactivated HAV vaccination series remained seroprotective for at least 5 years. Theoretically, such a vaccination program can provide a protective period of over 20 years in children. This paper may be the first to describe at least 5 years. Theoretically, such a vaccination program can provide a protective period of over 20 years in children. This paper may be the first to describe at least 5-year immunogenicity of inactivated HAV vaccination in healthy children.[SDGs]SDG3hepatitis a vaccine; antibody blood level; antibody titer; article; child; controlled study; enzyme linked immunosorbent assay; follow up; hepatitis a; hepatitis a virus; human; immunogenicity; major clinical study; priority journal; taiwan; vaccination; Child; Child, Preschool; Female; Hepatitis A Vaccines; Hepatitis A Virus, Human; Humans; Immunization Programs; Infant; Male; Sex Factors; Taiwan; Time Factors; Vaccines, Inactivated; Viral Hepatitis Vaccinesjournal article10.1016/S0264-410X(97)00179-596070352-s2.0-0031986247