CHYI-FENG JANLiu T.-H.Ho C.-H.Chien Y.-C.CHE-JUI CHANGFEI-RAN GUOKUO-CHIN HUANG2021-01-142021-01-1420200263-2136https://www.scopus.com/inward/record.uri?eid=2-s2.0-85080844412&doi=10.1093%2ffampra%2fcmz039&partnerID=40&md5=c0249cc6cf7b510b35140de81ec3541ehttps://scholars.lib.ntu.edu.tw/handle/123456789/540616Objectives: To determine the required hepatitis B vaccine doses for subjects who were seronegative for three hepatitis B seromarkers during their youth who wish to have seroprotective antibodies against the hepatitis B surface antigen (anti-HBs). Methods: We conducted a retrospective cohort study. From 2012 to 2015, graduate school students born after 1986 who were seronegative for three hepatitis B virus seromarkers at college entrance (n = 1037) were recruited. Four groups of subjects received zero to three doses of a hepatitis B vaccine booster at their free willingness, and their anti-HBs titre were measured at their graduate school entrance. Very low and extremely low antibody titres against the hepatitis B surface antigen were elucidated by graphic inference to determine the required booster dose cut-off value for seropositivity after revaccination. Results: The anti-HBs seropositive rates in the four groups of subjects receiving the hepatitis B booster vaccine(s) were 17.7%, 52.1%, 78.6% and 90.9% for those receiving zero, one, two and three doses, respectively. In subjects with very low antibody titres against the hepatitis B surface antigen after one dose of the vaccine booster and subjects with an extremely low titre after two doses of the booster, the seropositive rates reached 95% at the cut-off value of 3 mIU/ml. Conclusion: A seropositive rate of at least 95% can be reached by the administration of two hepatitis B booster doses to youths with extremely low antibody titres against the hepatitis B surface antigen (<3 mIU/ml) and administering one dose to those with very low titres (3-10 mIU/ml) at college. ? 2019 The Author(s) 2019. Published by Oxford University Press.[SDGs]SDG3hepatitis B antibody; hepatitis B surface antigen; recombinant hepatitis B vaccine; hepatitis B antibody; hepatitis B surface antigen; hepatitis B vaccine; adult; antibody titer; Article; cohort analysis; college student; controlled study; dose response; female; graduate student; health center; hepatitis B; Hepatitis B virus; human; male; retrospective study; revaccination; Taiwan; university hospital; adolescent; hepatitis B; immunology; procedures; secondary immunization; young adult; Adolescent; Adult; Cohort Studies; Female; Hepatitis B; Hepatitis B Antibodies; Hepatitis B Surface Antigens; Hepatitis B Vaccines; Humans; Immunization, Secondary; Male; Retrospective Studies; Taiwan; Young Adultjournal article10.1093/fampra/cmz039313758192-s2.0-85080844412