en Infectious Disease Infectious Disease Original Research Original Research <p style="margin: 0cm 0cm 12pt 5.4pt; text-align: justify;"><strong>Background: </strong>Accidental exposure to sharp instruments is an important problem for health care students. Thus, the aim of this study was to determine the rate of immunity in health care students 2 decades after national neonatal hepatitis B (HB) vaccination.<br> &nbsp;&nbsp; <strong>Methods:</strong> All junior students attending medicine, nursing and midwifery schools were screened for anti-HBs. One dose of hepatitis B vaccine was offered to all participants who did not have antibodies to HB surface antigen (anti-HBs) of > 10 IU/L; then, they were tested for anti-HBs after a month. The participants were classified into 3 groups: postboosting nonimmune, postboosting immune, and preboosting immune. Chi square test and ANOVA were used for data analysis.<br> <strong>&nbsp;&nbsp; Results:</strong> In the first step, 65.20% of participants did not show immunity, but after receiving a booster dose, only 6.0% remained nonimmune. The mean age of nonimmune students was significantly higher than that of students who had postboosting immune and preboosting immune status (p=0.001 and 0.002, respectively). Also, the mean injection time from last shot was higher in postboosting immune group compared to preboosting immune group (p<0.001). Also, prebooster anti-HBs level was significantly different among participants with suboptimal response and those who developed anamnestic response, indicating preserved immune memory (p=0.001).<br> &nbsp;&nbsp; <strong>Conclusion:</strong> High anamnestic response to HBV booster dose indicates sufficient immunity to HBV in the majority of health care students. However, identifying students who cannot respond to a booster dose of vaccine seems to be necessary at the beginning of health care courses.</p> <div style="font-style: normal;"></div> Hepatitis B, Vaccination, Medical student, Immunologic memory 114 119 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-974-5&slc_lang=en&sid=1 Behzad Bijani bbijani@qums.ac.ir 200319475328460062831 200319475328460062831 No Department of Infectious Diseases, Qazvin University of Medical Sciences, Qazvin, Iran Abbas Allami allami9@yahoo.com 200319475328460062832 200319475328460062832 Yes Department of Infectious Diseases, Qazvin University of Medical Sciences, Qazvin, Iran Farzaneh Jafari drjafari587@gmail.com 200319475328460062833 200319475328460062833 No Department of Infectious Diseases, Qazvin University of Medical Sciences, Qazvin, Iran Fatemeh Hajmanoochehri f.manoochehri@yahoo.com 200319475328460062834 200319475328460062834 No Department of Pathology, Qazvin University of Medical Sciences, Qazvin, Iran Soroush Bijani soroush.bijani@gmail.com 200319475328460062835 200319475328460062835 No Department of Pharmaceutical Biotechnology, Zanjan University of Medical Sciences, Zanjan, Iran