Objective: A prospective study was carried out in the well baby and immunization clinics of tertiary care hospital to compare the immunogenicity of low dose hepatitis B vaccine (HBV) given intradermally versus standard dose given intramuscularly.
Methods: One hundred ninety six term, healthy, Australia antigen negative and exclusively breast fed babies were allocated into two groups in a simple randomized manner. In group I, hepatitis B vaccine was given in low dose (2 mcg) by intradermal route whereas in group II it was administered in standard dose (10 mcg) by intramuscular route. Diphtheria, pertussis, tetanus (DPT) and oral polio vaccine (OPV) were co-administered with HBV in both the groups at 6, 10 and 14 weeks of age at different sites. One hundred seventy seven infants could be regularly followed up and tested for anti-HBs titres by third generation ELISA test using mono-ELISA anti-HBs 3.0 kits. Geometric mean titres of anti-HBs were estimated in each group and compared. Student's t-test was used for statistical analysis.
Results: Seroprotective anti-HBs titres (titre greater than 10 mIU/mL) were achieved in 87 of 88 (98.8 percent) children having received intramuscular doses as compared to 82 of 89 (92.1 percent) children in the intradermal group. The geometric mean titres of the intradermal group were 92.71 mIU/mL (95 percent C.I. 68.85-124.85), significantly lower than 331.66 mIU/mL (95 percent C.I. 245.12-448.78), noticed in the intramuscular group. There were no significant adverse reactions in both the groups. Hepatitis B vaccine is immunogenic when co-administered with DPT and OPV vaccine. The intradermal hepatitis B administration is less effective with lower immunogenicity than the intramuscular vaccination.