A randomised, double-blind, non-inferiority clinical trial on the safety and immunogenicity of a tetanus, diphtheria and monocomponent acellular pertussis (TdaP) vaccine in comparison to a tetanus and diphtheria (Td) vaccine when given as booster vaccinations to healthy adults.

BACKGROUND

Increasing incidence of pertussis in adolescents and adults has stimulated the development of safe and immunogenic acellular pertussis vaccines for booster vaccination of adolescents and adults.

PURPOSE: To obtain clinical documentation of the safety and immunogenicity of a tetanus, diphtheria and monocomponent acellular pertussis combination vaccine (TdaP), when given as a booster vaccination to adults.

METHODS

The trial was double-blind, controlled and randomised. 802 healthy adults, aged 18-55 years who had completed childhood vaccination with diphtheria, tetanus and whole cell pertussis vaccine (DTwP), were booster vaccinated with TdaP or Td. Blood samples were taken before and one month after the vaccination for serological analysis and adverse events were recorded during the one-month-follow-up period.

RESULTS

The monocomponent acellular pertussis vaccine (aP) in the TdaP vaccine was immunogenic in adults with 92.0% of TdaP vaccinated subjects obtaining an anti-pertussis toxin (anti-PT) antibody booster response. TdaP was non-inferior to Td in eliciting seroprotective anti-tetanus and diphtheria antibody concentrations with more than 98% of subjects obtaining post-vaccination seroprotective concentrations (≥ 0.1 IU/mL). T and d booster response rates were 93.0% and 97.5%, respectively. The frequencies of solicited local adverse reactions were low and comparable between TdaP and Td vaccinees. In the TdaP group, 30.7% reported pain, 4.2% swelling and 2.0% erythema at the injection site. The most frequent solicited general symptoms were headache (20.4%), fatigue (17.0%) and myalgia (10.0%). In the Td group, 35.7% reported pain, 2.5% swelling and 3.2% erythema at the injection site, whereas headache, fatigue and myalgia were reported by 15.7%, 14.5% and 12.5%, respectively. In conclusion, TdaP Vaccine SSI was safe and immunogenic when given as a booster vaccination to adults.