Abstract
ABSTRACTPertussis is a highly contagious disease, for which periodic peaks in incidence and an increasing number of outbreaks have been observed over the last decades. The reduced-antigen-content tetanus-diphtheria-acellular pertussis vaccine (Tdap) can be used to boost individuals aged ≥10 years, vaccinated in infancy with a diphtheria-tetanus-acellular pertussis vaccine (DTaP), to reduce pertussis morbidity and maintain protection against diphtheria and tetanus throughout adolescence and adulthood. This phase III, open-label, non-randomized, multicenter follow-up study (NCT01738477) enrolled 19–30-year-old participants from the United States who had received booster vaccination 10 years earlier with either Tdap (Tdap group) or Td (Td group). In total, 128 (Tdap group) and 37 (Td group) participants received Tdap vaccination. After administration of Tdap, all participants were seroprotected (antibody concentrations ≥0.1 international units [IU]/ml) against diphtheria and tetanus. Immune responses to a second Tdap dose in the Tdap group were shown to be non-inferior to responses elicited by a first Tdap dose in the Td group for diphtheria and tetanus and to a 3-dose DTaP vaccination during infancy for pertussis antigens (primary objectives). Post-booster vaccination, all participants in both groups had antibody concentrations above assay cut-offs and antibody geometric mean concentrations increased by 3.8–15.5-fold compared to pre-booster levels for all antigens. The incidence of adverse events was similar in the Td (80.6%) and Tdap (85.6%) groups (no serious adverse events reported). A Tdap dose administered after previous Td or Tdap vaccination was shown to be immunogenic and well-tolerated in young adults, supporting repeated vaccination with Tdap at 10-year intervals.
Highlights
Pertussis or whooping cough, a highly contagious respiratory tract infection caused by Bordetella pertussis, is rapidly transferred via respiratory droplets and manifests as severe coughing.[1]
We previously assessed the immunogenicity and safety of tetanus-diphtheriaacellular pertussis vaccine (Tdap) (Boostrix, GSK) compared to a control Td vaccine (MassBiologics) administered as booster vaccination in 10–18-year-olds who had received primary immunization with whole-cell or acellular DTP vaccines.[29]. In this follow-up study, we evaluate the non-inferiority of a second Tdap booster dose with respect to immune responses to diphtheria and tetanus when compared with that of a first dose in participants having received a Td booster dose 10 years earlier and to pertussis antigens when compared with a 3 dose-series of a diphtheria-tetanus-acellular pertussis vaccine (DTaP) vaccine (Infanrix, GSK) in infants who received this vaccine in a German household contact efficacy study.[30]
The immune responses to diphtheria and tetanus elicited by a second Tdap dose were shown to be non-inferior to a first Tdap dose following previous Td booster immunization, as the lower limits (LLs) of the 95% confidence intervals
Summary
A highly contagious respiratory tract infection caused by Bordetella pertussis, is rapidly transferred via respiratory droplets and manifests as severe coughing.[1]. 14-year-olds in European countries in 2015.11 The cause of periodic outbreaks, which follow the natural cycle of disease, is multifaceted.[12,13] Immunity following both natural infection and vaccination is short-lived, likely due in part to pathogenic evolution and, pertussis vaccines reduce disease severity, they might be more limited in preventing transmission than previously anticipated.[12,14,15] Following the switch from wholecellular to acellular pertussis vaccines due to safety concerns, 16 an increase in pertussis infections has been reported in several countries,[6,7,8,9,10] as the antibody persistence after acellular versus whole-cell pertussis vaccination seems to be more prone to decline.[17]
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