Immunogenicity and safety of one dose of diphtheria, tetanus, acellular pertussis and poliomyelitis vaccine (Repevax®) followed by two doses of diphtheria, tetanus and poliomyelitis vaccine (Revaxis®) in adults aged ≥40 years not receiving a diphtheria- and tetanus-containing vaccination in the last 20 years☆

Abstract Introduction The immunogenicity and safety of one dose of Tdap-IPV (tetanus, diphtheria, acellular pertussis and inactivated poliomyelitis vaccine) and two doses of Td-IPV (tetanus, diphtheria and inactivated poliomyelitis vaccine) were assessed in adults who had not received a diphtheria- and tetanus-containing vaccine in the last 20 years. Methods This open-label, multicentre study was conducted in adults aged ≥40 years with no diphtheria- and tetanus-containing vaccine in the last 20 years. Participants received one dose of Tdap-IPV followed by two doses of Td-IPV (0, 1, 6 month schedule). Primary immunogenicity objectives: to demonstrate acceptable seroprotection rates (percentage of participants with antibody titre above threshold) post-dose 3 for diphtheria (≥0.1 IU/mL by seroneutralization assay [SNA]); tetanus (≥0.1 IU/mL by enzyme-linked immunosorbent assay [ELISA]); and poliomyelitis (≥8 1/dil by SNA); and to evaluate the percentage of participants with an antibody concentration ≥5 EU/mL (by ELISA) for pertussis antigens post-dose 1. Seroprotection rates were acceptable if the lower limit of the 95% confidence interval (CI) was >95%. Percentage of participants with basic clinical immunity against diphtheria (≥0.01 IU/mL) was also assessed. Safety (adverse events [AEs] and serious AEs) was assessed after each dose. Results Overall, 336 participants were included (mean age: 60.2 years). Post-dose 3 seroprotection rates were: diphtheria, 94.6% (CI 91.5–96.8); tetanus and poliomyelitis, 100% (CI: 98.8–100). Percentage of participants with an antibody titre ≥5 EU/mL against pertussis antigens was ≥95.8% for all five pertussis components. Basic clinical immunity against diphtheria was achieved in 100% (CI: 98.8–100) of participants. AEs were reported more frequently following vaccination with Tdap-IPV (post-dose 1: 65.3%) than with Td-IPV (post-dose 2: 48.3%; post-dose 3: 50.3%). Conclusions This study highlights the benefits of using Tdap-IPV followed by two doses of Td-IPV in an adult population to achieve maximal protection against diphtheria, tetanus, poliomyelitis and pertussis simultaneously.