We conducted the study to evaluate the immunogenicity and safety of three component DTaP vaccine (Infanrix®) in a group of Korean healthy infants on a three-dose primary vaccination. And we compared the immunogenicity of this DTaP vaccine with two component DTaP vaccine which has been widely used in Korea.

We enrolled one hundred fifty one healthy infants aged 8-9 weeks. These infants were vaccinated at age 2, 4 and 6 months of age with three component DTaP vaccine. Solicited adverse events were actively monitored for 72 hours following each vaccination, and all adverse events after each vaccination were observed for three weeks. Anti-diphtheria toxoid Ab., anti-tetanus toxoid Ab., anti-pertussis toxin Ab., anti-filamentous hemagglutinin Ab., and anti-pertactin Ab. were measured using ELISA for assessing immunogenicity of study vaccine in 60 infants. Immunogenicity analysis of two component DTaP vaccine was performed with same methods in 14 infants as control.

The seroconversion rates of anti-diphtheria toxoid Ab, anti-tetanus toxoid Ab. anti-filamentous hemagglutinin Ab. were 100% in both group. Seroconversion rate of anti-pertactin Ab in study group was 100%, but the rate in control group was 50%. However, geometric mean concentration of anti-pertussis toxin Ab. was higher in control group. Mild local and systemic reactions were observed within three days after vaccination, and no serious adverse events related study vaccine were happened during study period.

Our study results suggest that three component DTaP vaccine (Infanrix®) is a well-tolerable and high immunogenic vaccine, especially anti-Pertactin Ab. of the study vaccine is very immunogenic. It can be available as routine DTaP vaccination in our infants.