Efficacy of Shanvac-B recombinant DNA hepatitis B vaccine in health care workers of Northern India.

BACKGROUND: Health care workers (HCWs) constitute a high-risk population of HBV infection. There are limited data on the efficacy of vaccination in HCWs in India. This study was to evaluate the efficacy of indigenous recombinant hepatitis B vaccine, Shanvac-B, in HCWs. METHODS: In 597 HCWs screened before the vaccination, 216 (36.2%) showed the presence of at least one of the markers of HBV/HCV infection. Of the remaining 381 (63.8%) HCWs who were considered for vaccination, only 153 (age 18-45 years; 48 males and 105 females) were available for final assessment. These HCWs received 20 μg of vaccine at 0, 1 and 6 months. They were asked for the reactogenicity and monitored for the seroprotective efficacy of the vaccination. Anti-HBs titres were measured after vaccination at 1, 2 and 7 months. The presence of anti-HBs titers equal to 1 MIU/ml was considered as seroconversion and that of titres greater than 10 MIU/ml as seroprotection. RESULTS: After vaccination, 32 males (67%) and 76 females (72%) showed seroconvertion; finally 12 (25%) of the males and 47 (45%) of the females were seroprotected. Seroprotection at 2 and 7 months was more dominant in the females than in the males (96% vs. 56%, P=0.001, 100% vs. 85%, P=0.0001), respectively. Geometric mean titres of anti-HBs after vaccination were also higher in the females than in the males (257±19.7 vs. 29±1.88 MIU/ml, P=0.01, 1802±35.2 vs. 306±13.6 MIU/ml, P≤0.05, 6465±72 vs. 2142±73.6 MIU/ml, P＜0.05). Seven male HCWs showed unsatisfactory response, non-response (n=3, 6%) and hypo-response (≤10 MIU/ml, n=4, 8%) at the end of vaccination. Smoking and alcoholism were significantly correlated with unsatisfactory response. No significant adverse effects of vaccination were observed in any HCW. CONCLUSIONS: The presence of HBsAg in HCWs indicates that a high proportion of HCWs are infected with HBV and HCV in India. Recombinant indigenous vaccine Shanvac-B is highly efficacious in HCWs, and its immunogenicity is significantly higher in females than in males. However, prevaccination screening of HCWs is strongly recommended in India.