title: Anti-diphtheria antibody seroprotection rates are similar 10 years after vaccination with dTpa or DTPa using a mathematical model.
abstract: The reduced antigen content diphtheria, tetanus and pertussis (dTpa) vaccine (Boostrixtrade mark) has been shown to induce a strong booster response to all the vaccine components in 4-6 year olds. However, anti-diphtheria antibody levels were observed to be lower when compared to the "full strength" paediatric DTPa vaccine. To assess the impact of this difference on long-term protection, a mathematical model was developed to predict diphtheria antibody decay over time. The model was based on a linear decrease in log-transformed antibody concentrations after the first year post-vaccination. When applied to data collected 3.5 years after vaccination of 4-6 year olds with either DTPa or dTpa, the model predicted that 10 years post-vaccination, 98.6% of subjects vaccinated with dTpa were likely to remain seroprotected against diphtheria, compared to 99.6% vaccinated with DTPa. Therefore, the difference observed in diphtheria antibody geometric mean concentrations 1 month after booster vaccination at 4-6 years with dTpa or DTPa is unlikely to be of clinical relevance 10 years later at the time of the adolescent booster.
authors.affiliation: GlaxoSmithKline Biologicals, Rue de l'Institut 89, B-1330 Rixensart, Belgium. brigitte.cheuvart@gskbio.com
authors.forename: Brigitte
authors.initials: B
authors.lastname: Cheuvart
authors.forename: Margaret
authors.initials: M
authors.lastname: Burgess
authors.forename: Fred
authors.initials: F
authors.lastname: Zepp
authors.forename: Jussi
authors.initials: J
authors.lastname: Mertsola
authors.forename: Joanne
authors.initials: J
authors.lastname: Wolter
authors.forename: Lode
authors.initials: L
authors.lastname: Schuerman
mesh_terms: D000328:Adult; D000907:Antibodies, Bacterial / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D004165:Diphtheria / Q000276:immunology*; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000276:immunology*; D006801:Humans; D007115:Immunization Schedule; D007117:Immunization, Secondary; D008954:Models, Biological; D016032:Randomized Controlled Trials as Topic; D013997:Time Factors; D014611:Vaccination / Q000379:methods
chemical_list: D000907:Antibodies, Bacterial; D015721:Diphtheria-Tetanus-Pertussis Vaccine