Immunogenicity and safety results from a randomized multicenter trial comparing a Tdap-IPV vaccine (REPEVAX®) and a tetanus monovalent vaccine in healthy adults

UNLABELLED In adults with a tetanus-prone injury, combined vaccines such as Tdap-IPV (REPEVAX®) can boost immunity against several diseases simultaneously. This Phase IIIb, parallel-group, open-label trial compared antibody responses to Tdap-IPV and tetanus monovalent vaccine (TMV; Vaccin Tétanique Pasteur® or Tetavax®) against tetanus toxoid 10 and 28 d post-vaccination. Between July and December 2009, four centers in France and five in Germany recruited healthy adults who had received a tetanus-containing vaccine 5-10 y previously. Participants were randomized 1:1 to receive at the first visit a single dose (0.5 mL) of Tdap-IPV or TMV, with follow-up visits at Day 10 and Day 28. OUTCOMES per protocol (PP) population immunogenicity at Day 10 (primary) and at Day 28 (secondary); safety throughout the study. Of 456 adults randomized, 223 received Tdap-IPV and 233 received TMV (PP population: 183 and 199 participants, respectively). All participants receiving Tdap-IPV and 99.0% receiving TMV had an anti-tetanus antibody concentration ≥ 0.1 IU/mL, confirming non-inferiority of Tdap-IPV to TMV (95% confidence interval of the difference: -1.2, 3.6). Number of adverse events reported was comparable in each group. Injection-site reactions were reported by 76.6% participants receiving Tdap-IPV and 74.6% receiving TMV. Systemic events (e.g., malaise, myalgia and headache) were reported in 47.7% and 39.7% of the Tdap-IPV and the TMV groups, respectively. Tdap-IPV is effective and well-tolerated for use in the management of tetanus-prone injuries in emergency settings in persons for whom a booster against diphtheria, pertussis and poliomyelitis is also needed.