Immunogenicity of recombinant hepatitis B vaccine in health care worker of Boo-Ali hospital in Tehran, Iran, 2002-2004

Background: Although recombinant hepatitis B vaccine is effective in a majority of population, a significant percent may do not response (up to 10%). Old age, obesity, heavy smoking and immunologic impairment have been associated with lower anti –HBs responses. In the present study, the efficacy of vaccine and effects of the abovementioned factors have been evaluated. Materials and methods: Of 111 health care workers in Boo-Ali hospital, 72 participants completed primary vaccination series and antibody tittering. They received 20µg of recombinant HBV vaccine (Heberbiovac, Cuba) in standard schedule. Anti-HBs was determined by ELISA test (Diakey, South Korea) one month following the third dose. Results: The lowest completion rate was reported among nursing staff and physicians (17%). Seroprotection (anti-HBs ≥10IU/L) was achieved in 86.1% of participants. Among seroprotected individuals, 52.8% were low-responders (antiHBs titer of 10-99IU/L) and 33.3% were good responders (anti-HBs titer of >100IU/L). The independent predictors of responsiveness were age less than 40 (OR=3.5, 95%CI=1.8-14.6, p<0.05), non-smoking status (OR=2.9, 95%CI=1.517.2, p<0.05), and body mass index less than 25kg/m 2 (OR=4.3, 95%CI=1.9-18.0, p<0.05). Of 10 non-responders, 7 received booster dose while anti-HBs titer was determined only in one. Conclusion: The primary factors associated with completion of immunization may not be amenable to job-education level. Non-compliance among non-responders was quite high (90%). This situation seems to be grim for health care workers and warranted appropriate interventions.