Objective: The objective of this study was to perform a pooled analysis of the immunogenicity and reactivity results obtained in 2 trials carried out in Spain with a combined DTP-HB vaccine.
Patients and methods: Vaccine was administered according to one of two existing vaccination schedules: 2-4-6 and 3-5-7 months of age. Blood samples for antibody determination were obtained 3-6 weeks after the third dose. Anti-diphtheria, anti-tetanus and anti- B. pertussis antibodies were measured by ELISA and anti-HB by radioimmunoassay. Local and general signs and symptoms were recorded by the parents on diary cards for a 4-day follow-up period after each vaccination.
Results: A total of 231 infants received three doses of DTP-HB vaccine. All of these doses were accompanied by the corresponding diary card (693 data points for the evaluation of reactogenicity). Two-hundred and nineteen subjects ere included in the analysis of immunogenicity. After the full vaccination course, all subjects had sero-protective titers against diphtheria, tetanus and hepatitis B and were sero-positive of B. pertussis. Geometric mean titers of anti-HB antibodies was 1986 mIU/ml. Pain at the injection site (64%) and unusual crying (71.5%) were the most frequently reported local and general symptoms, respectively. Fever (rectal temperature > or = 38 degrees C) was reported after 46% of the doses, but was considered as severe (> 39.5 degrees C) only in 5 cases.
Conclusions: These results show that this combined DTP-HB vaccine induced a strong immune response to all vaccine components. The safety profile of this DTP-HB is similar to that of classical DTP vaccines.