INTRAMUSCULAR VERSUS INTRADERMAL ADMINISTRATION OF A RECOMBINANT HEPATITIS-B VACCINE - A COMPARISON OF RESPONSE RATES AND ANALYSIS OF FACTORS INFLUENCING THE ANTIBODY-RESPONSE

In an open controlled study 286 health care workers in Stockholm, Sweden, received 20-mu-g of a recombinant hepatitis B vaccine (Engerix B(R)) by the intramuscular route, and 383 2-mu-g by the intradermal route. Seroconversion to protective anti-HBs levels (anti-HBs titre greater-than-or-equal-to 10 IU/l) was achieved in 94% of the i.m. and 89% of the i.d. vaccinees. Female sex, intramuscular vaccination, young age, and being a non-smoker were associated with a higher response rate and a higher geometric mean anti-HBs titre than male sex, intradermal vaccination, old age and being a smoker. If an acceptable response rate to protective anti-HBs levels of 85% is cho-en, intradermal vaccination can be used as a cost reducing strategy for all women and for non-smoking men < 30 years of age, as estimated in a logistic regression model. Due to the variable antibody response in different individuals, post vaccination testing for anti-HBs titres is recommended in health care workers, regardless of vaccination route.