Vaccine 29 (2011) 2727–2729 Contents lists available at ScienceDirect Vaccine journal homepage: www.elsevier.com/locate/vaccine Immunity to hepatitis B vaccine among health care workers Mohammad Hossein Baghianimoghadam a , Mahmod Nouri Shadkam b , Hossein Hadinedoushan c,∗ a Health Services Dep., Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran b Pediatrics Dep., Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran c Immunology Dep., Shahid Sadoughi University of Medical Sciences and Health Services, Daneshjoy Blv., Pirapezeshki, Yazd, Iran article info Article history: Received 19 August 2010 Received in revised form 18 January 2011 Accepted 27 January 2011 Available online 23 February 2011 Keywords: Immunity Hepatitis B vaccine College students abstract The aim of this study was to determine the level of anti-HBsAg (hepatitis B surface antigen) in vaccinated high risk group. We measured anti-HBsAg concentration in blood sera of adult students aged from 19 to 37 years old. Five milliliters (5 ml) of blood sample was taken from 210 cases four months after the second dose and 126 out of 210 cases three months after the third dose of hepatitis B vaccination. All blood samples were analyzed for anti-HBsAg by ELISA method. 125 out of 210 samples (59.5%) showed anti- HBsAg concentrations higher than 20 mIu/ml and considered immune after the second dose of hepatitis B vaccination. Also, 99.2% of samples had anti-HBsAg higher than 20 mIu/ml three months after the third dose of the vaccination. Non-immune cases in males were more than females (41.2% vs.40.1%). In conclusions, our results reinforce the importance of hepatitis B vaccine in adolescents and suggest that three dose of hepatitis B vaccine is necessary to increase the seropositive rate of anti-HBsAg in adults. © 2011 Elsevier Ltd. All rights reserved. 1. Introduction Hepatitis B virus (HBV) is a double strand, enveloped DNA virus of the hepadnaviridae family, which replicates in the liver and causes hepatic dysfunction [1]. The currently acknowledged risk factors for infection by HBV are sexual promiscuity, intravenous drug abuse, blood and derivatives transfusions, hemodialysis and needle accidents among healthcare workers. The HBV is transmit- ted through serum and even body fluids such as semen, saliva, sweat, tears or breast milk [2]. Hepatitis B is one of the most common infectious diseases in the world. It is estimated that one third of the world’s popula- tion has been infected and over 350 millions people are chronic carriers. HBV infection results in an estimated 620,000 to 1 mil- lion death annually [3]. In the United States more than 330,000 new cases of hepatitis B occur per year [4]. Infection with hepatitis B virus may progress to chronic liver diseases including cirrho- sis and hepatocellular carcinoma, one of the most common kinds of cancers in the world. Following acute HBV infection, between 1–10% of adults and 30–90% of children become chronic carries, a part of whom at risk of developing life threatening disease [5]. Chronic hepatitis B is a cause of morbidity and mortality world- wide. ∗ Corresponding author. Tel.: +98 351 6233235; fax: +98 351 6238561. E-mail address: hhadin@ssu.ac.ir (H. Hadinedoushan). There are a large number of hepatitis B carriers in Iran. It is esti- mated that over 35% of Iranians have been exposed to the HBV and about 3% are chronic carriers, ranging from 1.7% in Fars province to over 5.1% in Golestan [6,7]. The discovery that passively acquired anti-hepatitis B surface antigen (anti-HBsAg) could protect individuals from acute clinical hepatitis B and chronic HBV infection if given soon after exposure led to the development of a specific antibody containing high titer of anti-HBsAg. Vaccination against hepatitis B is the most effective measurement to control and prevent hepatitis B on global scale [8]. Safe, immunogenic and effective hepatitis B vaccines have been commercially available in the United State since 1981. In Iran, vaccination against HBV has been routinely performed for all infants that were born to HBsAg negative mothers and high-risk groups since 1992. The protective efficacy of hepatitis B vaccination is directly related to development of anti-HBsAg [9]. Anti-HBsAg levels of 10 mIu/ml or higher are considered to be 100% protected against clinical illness and chronic infection. The vaccines produced by each manufacturer have been evaluated in clinical tri- als to determine the age-specific dose that achieves the maximum seroprotection rate. There are few studies focused on the seropositive rate of protec- tive antibody, named anti-HBsAg, among adolescents in Iran. The objective of the present study was to determine the level of anti- HBsAg and immunity to hepatitis B infection in vaccinated high risk group. To achieve the purpose of the study, anti-HBsAg concentra- tion in blood sera of vaccinated students aged from 19 to 37 years old were collected and analyzed. 0264-410X/$ – see front matter © 2011 Elsevier Ltd. All rights reserved. doi:10.1016/j.vaccine.2011.01.086