Antibody persistence 2 and 3 years after booster vaccination of adolescents with recombinant acellular pertussis monovalent aPgen or combined TdaPgen vaccines
Punnee Pitisuttithum, Jittima Dhitavat, Chukiat Sirivichayakul, Arom Pitisuthitham, Yupa Sabmee, Pailinrut Chinwangso, Chawanee Kerdsomboon, Librada Fortuna, Jane Spiegel, Mukesh Chauhan, Indrajeet Kumar Poredi, Anita H.J. van den Biggelaar, Wassana Wijagkanalan, Simonetta Viviani, Souad Mansouri, Hong Thai Pham
Abstract
Background Recombinant pertussis vaccines inducing long-lasting immune responses could help to control the rise in pertussis. We here report on persisting antibody responses 2 and 3 years after booster vaccination with a new generation recombinant acellular pertussis vaccine. Methods Participants of a phase 2/3 randomised-controlled clinical trial with a monovalent pertussis vaccine containing genetically inactivated pertussis toxin (aP gen ) or its tetanus and diphtheria toxoids combination (TdaP gen ), or a chemically detoxified comparator vaccine (Tdap chem ), (originally conducted between July and August 2015) were invited to participate in observational studies of persisting antibody responses 2 and 3 years after vaccination. Serum IgG against pertussis toxin (PT-IgG) and filamentous hemagglutinin (FHA-IgG) were assessed by ELISA, and PT-neutralising antibodies (PT-Nab) by Chinese Hamster Ovary cell assay. Findings Waning of antibodies stabilised in aP gen and TdaP gen vaccinees 2 and 3 years after vaccination. Three years post-vaccination PT-neutralising antibodies remained 4·6-fold (95% Confidence Interval (CI) 2·6–8·1) and 3·7-fold (95% CI 2·2–6·1) higher, PT-IgG antibodies 3·0-fold (95% CI 2·2–4·1) and 2·5-fold (95% CI 1·9–3·3) higher, and FHA-IgG antibodies 1·8-fold (95% CI 1·3–2·5) and 1·6-fold (95% CI 1·2–2·1) higher than baseline in aP gen and TdaP gen recipients, respectively. In the Tdap chem group, PT-neutralising and PT-IgG and FHA-IgG antibodies were back at baseline levels 2 years post-vaccination. Three years post-vaccination seroconversion rates for PT-neutralising antibodies were 65·0% (95% CI 44·1–85·9) and 55·0% (95% CI 33·2–76·8) in aP gen and TdaP gen recipients, respectively. Interpretation Considering the persistence of elevated antibody responses 3 years post-booster vaccination, genetically detoxified monovalent aP gen and TdaP gen vaccines can be expected to induce longer-lasting protection than chemically inactivated Tdap vaccines. Funding BioNet-Asia