The recent increase of pertussis in young adults in Japan is hypothesized to be due in part to waning protection from the acellular pertussis vaccine. While a booster immunization may prevent an epidemic of pertussis among these young adults, little is known about the safety and immunogenicity of such a booster with the diphtheria, tetanus, and acellular pertussis vaccine (DTaP), which is currently available in Japan. One hundred and eleven medical students with a mean age of 19.4 years were randomly divided into 2 groups of 55 and 56 subjects and received 0.2 or 0.5 mL of DTaP, respectively. Immunogenicity was assessed by performing the immunoassay using serum, and the geometric mean concentration (GMC), GMC ratio (GMCR), seropositive rate, and booster response rate were calculated. Adverse reactions and adverse events were monitored for 7 days after vaccination. Significant increases were found in the antibodies against pertussis toxin, filamentous hemagglutinin, diphtheria toxoid, and tetanus toxoid after booster vaccination in both groups, and the booster response rates for all reached 100%. Both GMCs and GMCRs against all antigens were significantly higher in the 0.5-mL group than in the 0.2-mL group. No serious adverse events were observed. Frequencies of local reactions were similar between the 2 groups, although that of severe local swelling was significantly higher in the 0.5-mL group. These data support that booster immunization using both 0.2 and 0.5 mL of DTaP for young adults is acceptable for controlling pertussis. (This study has been registered at UMIN-CTR under registration no. UMIN000010672.).
Journal:Clin Vaccine Immunol. 2013