Immunogenicity and Safety of a Combined Hepa-PDT Vaccine

Choi, Seung Hee; Choi, Young Youn; Hwang, Tae Ju; Kook, Myung Hee

Abstract

The universal vaccination against hepatitis B in early infancy is the only effective way to control the hepatitis infection in highly endemic area as in Korea. The purpose of this study was to evaluate the immunogenicity and safety of the combined DPT and Hepatitis B vaccine administering at 2, 4, 6 months of chronologic age who was born to HBs Ag negative mother. Seventy healthy term and preterm infants from the Well Baby Clinic at Chonnam University Hospital and Kwangju Veterans Hospital were enrolled. The babies were divided into two groups. In control group(N=34), the infants received Hepavax-B 0.5ml(inactivated HBs Ag protein 10microg) intramuscularly and purified PDT vaccine 0.5ml subcutaneously separately. In the study group(N=36), combined Hepa-PDT (GCC-91-010) vaccine was administered at the same intervals. Antibody titers were assessed by RIA for anti-HBs and by ELISA for anti-DPT at two months of age just before the first vaccination and at seven months, one month after the third dose. Antibody level over 10mIU/ml was regarded as protective for both vaccinations. We compared the seroconversion rates between the two groups, and those between the premature and term infants in each group as well. Side effects were also assessed. The results were as follow: 1. The seroconversion rate of DPT was 100% for each group and that of hepatitis B was 83.3% in the study group, while 94.1% in the control group. The immu- nogenicity of both group was not different statistically. 2. The seroconversion rate of hepatitis B was 90.0%(18/20) in preterm infants and 88.0%(44/50) in term infants. 3. The side effect was negligible, occurring in one in each group as a minor illness. In conclusion, the results suggest that the combined DPT and Hepatitis B vaccine is as effective as conventional method in terms of provoking immune response in healthy infants born to HBsAg negative mothers without having additional side effects. This method seemed to have advantages of giving less shots in addition to possible better compliance than conventional method. Further improvement of the vaccine, however, is needed to attain a perfect seroconversion rate.