Intradermal hepatitis B vaccination in health care workers. Response rate and experiences from vaccination in clinical practise.

Health care workers at risk for hepatitis B virus infection are recommended for vaccination. Low-dose intradermal (i.d.) administration of vaccine has been suggested as a less expensive alternative to intramuscular (i.m.) inoculation. To evaluate the i.d. vaccination route, health care workers were included in a prospective study. The subjects were vaccinated with 0.1 ml (= 2 microg) recombinant vaccine (Engerix B, SmithKline Beecham) i.d. at 0, 1 and 6 months. Two months after the third vaccination, measurement of the anti-HBs level was conducted. An anti-HBs level > or =10 IU/l was considered protective. Those with an anti-HBs level <10 IU/l were given a fourth dose with new serological control after another 2 months. The results are based on the 1406 subjects that it was possible to evaluate. The seroconversion rate to protective anti-HBs level after 3 doses was 68% and after 3 or 4 doses 89%. Factors associated with a lower response rate were increasing age (p<0.05) and smoking (p<0.001). Sex or body mass index had no influence on the results. Vaccination technique seems to be of utmost importance when the i.d. route is used. Well instructed and experienced nurses are required and quality control with follow-up of overall seroconversion rate within each centre is needed.