en Infectious Diseases Infectious Diseases Original Article Original Article <p><span style="font-size:14px;"><span style="font-family:times new roman;"><em><span style="color:#0000FF;"><strong>Background:</strong></span></em> In Iran scince 1992, hepatitis B vaccination was a part of the national vaccination program. Hepatitis B vaccination is effective in the epidemiology of hepatitis B. The aim ofthis study was to evaluate the long &ndash; term persistence of immunity.<br> <em><span style="color:#0000FF;"><strong>Methods</strong>:</span></em> This cross-sectional analytical study was conducted on children and adolescents aged between 6-18 years in Birjand, who received a three &ndash; dose hepatitis B vaccination in accordance with the national immunization program. No students were infected with hepatitis B. Antibody titer higher than10 IU/L was considered positive.<br> <em><span style="color:#0000FF;"><strong>Results:</strong> </span></em>A total of 530 patients (307 boys and 223 girls) were recruited for the study of which 44% had positive antibody titer (&ge;10 IU / L). The geometric concentration mean (GMCs) of antibody in subjects was 64.9&plusmn;34.2, HBS antibody titer was positive in 40.4% of the boys and 59.6% of the girls. A significant difference in antibody titers was observed in terms of gender and according to the time elapsed since the last vaccination. Antibody titer in children older&nbsp; than 13 years had passed since their last vaccination and was significantly less than those children younger than thirteen years old had passed since their vaccination logistic regression analysis showed that the only predictive factor of anti-HBS low titer (<10 IU/L) is elapsed time of vaccination.<br> <em><span style="color:#0000FF;"><strong>Conclusions: </strong></span></em>Based on results of this study hepatitis B vaccine has created a good level of protection in 44% of the adolescents after 17 years</span></span></p> Hepatitis B, Vaccination, Infant, Anti-HBS antibody, Immunity 184 188 http://caspjim.com/browse.php?a_code=A-10-660-1&slc_lang=en&sid=1 Zohreh Azarkar Drz.azarkar@yahoo.com 100319475328460012073 100319475328460012073 No Infectious Disease Researches Center, Birjand University of Medical Sciences, Birjand, Iran Azadeh Ebrahimzadeh mri44556677@gmail.com 100319475328460012074 100319475328460012074 Yes Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran Gholamreza Sharifzadeh Rezamood@gmail.com 100319475328460012075 100319475328460012075 No Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran Masood Ziaee Dr.m.ziaee@gmail.com 100319475328460012076 100319475328460012076 No Infectious Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran Mohammad Fereidouni fery1351@yahoo.com 100319475328460012077 100319475328460012077 No Asthma, Allergy and Immunology Researches Center, Medical Sciences of University, Birjand, IRAN Fatemeh Taheri FatemehTaheri@gmail.com 100319475328460012078 100319475328460012078 No Birjand Atherosclerosis and Coronary Artery Researches Center, Birjand University of Medical Sciences, Birjand, Iran