Immunogenicity and Economic Evaluation of Different Recombinant Hepatitis–b Vaccines in Different Dosages, Schedules, and Routes of Administration

Objective: To measure the immunogenic response produced by recombinant DNA derived vaccines in different dosages, schedules, and routes of administration. Another objective was to evaluate the minimum dosage and compliant schedule of recombinant DNA derived vaccine required to produce effective immune response and its economic evaluation in the adult population. Methodology: Five hundred fifty eight healthcare workers in the age group of 20-50 years from Military Hospital Rawalpindi, Pakistan and other sister institutions were enrolled. Two hundred fifty eight were excluded due to serological evidence of HBV infection. Remaining three hundred were divided into five groups each having sixty volunteers with equal male to female ratio and age groups 20-29,30-39, 40-50. First four groups were injected with Heberbiovac vaccine and last group-V was given inj. Engerix–B. In Heberbiovac arm: Group-I received standard dose of 20μg at standard schedule of zero, one and six months intramuscularly. In Group-II, dose was reduced to half (10μg) intramuscularly. Group-III was given only two standard doses of 20μg at zero and one month interval intramuscularly and Group-IV received intradermal dose of 3μg at zero, one & six months. Group-V was given Engerix –B in standard dosage & schedule, (i.e., 20μg at zero, one and 6 months). Immunogenic response was measured in all the groups eight weeks after the last dose. Response was measured with MEIA/IMX system by ABBOTT. Results: Both the vaccines were equally immunogenic but higher titers of Anti HBs was achieved with Heberbiovac. In Heberbiovac arm of study, seroprotection rate was 96.36% in Group-I, in Group-II it was 94.64%, in Group-III 95% and in intradermal group 98.14%. In Engerix –B group it was 92%. Conclusion: Two doses/Half dose schedule/intradermal route of 3μg of Inj. Heberbiovac is equipotent to that of standard dose/schedule of Inj. Heberbiovac or Inj. Engerix–B in terms of seroprotection rate achieved.