The immunogenicity and safety of DTaP interchangeable immunization among Korean children

Since the production of various vaccine formulations by different pharmaceutical companies and interruptions in vaccine supply cannot be fully regulated, problems caused by DTaP interchangeability may occur. However, the interchangeability data on the first primary series of DTaP vaccination have not been well described. In this study we investigated immunogenicity and overall safety of diphtheria, tetanus, pertussis in children who had adventitiously received an interchangeable DTaP vaccination. A total 97 of participants were enrolled (mean age, 11 months). High immunogenicity (1.8 ± 0.4 IU/mL, 100%) was noted against diphtheria toxoid, and similar high immunogenicity (3.2 ± 2.1 IU/mL, 100%) was noted against tetanus toxoid. Immunogenicity against pertussis antigen was significantly greater in the interchangeable vaccinated group compared to the control group, and 57% of the interchangeable vaccinated subjects achieved high levels of protective immunity (45.2 ± 21.5 E U/mL). No serious adverse effects were noted, and most adverse effects resolved without treatment. The immunogenicity against each antigen was high in patients who were interchangeably vaccinated for DTaP. Our results provide clinical evidence affirming the non-inferiority of interchangeable vaccination when it cannot be avoided such as in limited vaccine supply situations or different prices.