Immunization against hepatitis B: comparison of immune response to intradermal, intramuscular, and combined vaccination

Background and Purpose: Immunogenicity studies of the plasma derived vaccine showed it to be highly effective. Due to the relatively high cost of immunization and need of large scale protection of the high risk groups, comparative studies of the vaccine effectiveness with intramuscular (IM) and intradermal (ID) administration were conducted, yielding no significant effectiveness difference between the two routes of administration. Material and Methods: Recombinant hepatitis B vaccine was given to 218 helath workers using three different of administration. Recombinant DNA vaccine was administered to 218 health care workers aged 20-60 years. IM in 72 ID in 115, and IMID (intramuscular intradermal) in 31 subjects. Antibodies to hepatitis B surface antigen (anti-HBs) were detected by the method of enzime radioimmunoassay. Results: The rate of seroconversion was 90.3% for intramuscular, 33.9% with a low mean antibody titer (24 mlU/mL) for intradermal, and 100% with a relatively low mean antibody titer 94/mlU/mL) for combination route of vaccination administration. Statistical analysis using t-test showed a significantly better response to IM and IMID than to ID route of Vaccination (p=0.0001) There was no statistically significant sex difference in the rate of seroconversion and antibody titer. Conclusion: The intramuscular route is recommended as the most appropriate roue of vaccination for health care workers.