Inadequate response to intradermal hepatitis A vaccine

To assess the efficacy of the intradermal route of administration of hepatitis A vaccine we conducted a study in hospital laboratory workers. Forty-three volunteers were given three different combinations of intradermal and intramuscular hepatitis A vaccine and compared with 18 controls given intramuscular vaccine only. The geometric mean titres (GMT) after one, two and three intradermal doses of 0.1 ml each were 4.5, 28 and 143 IU l-1 respectively. The GMT after one intramuscular dose in the controls was 163 IU l-1. The results indicate that the response to intradermal hepatitis A vaccine is poor and its use cannot be recommended.