Immunogenicity, safety, and reactogenicity of combined reduced-antigen-content diphtheria-tetanus-acellular pertussis vaccine administered as a booster vaccine dose in healthy Russian participants: a phase III, open-label study.

As vaccine-induced immunity and protection following natural pertussis infection wane over time, adults and adolescents may develop pertussis and become transmitters to unprotected infants. In Russia, diphtheria and tetanus but not pertussis-containing vaccines are registered for older children, adolescents, or adults. The reduced-antigen-content diphtheria toxoid, tetanus toxoid, and acellular pertussis (dTpa) vaccine (Boostrix, GSK) was developed for booster vaccination of children ≥4 years of age, adolescents, and adults. A phase III, open-label, non-randomized study was performed in eight centers in Russia between January and July 2018. The objective of this study was to assess immunogenicity, reactogenicity and safety of a single dose of dTpa vaccine in healthy Russian participants ≥4 years of age (age categories 4-9 years, 10-17 years, 18-64 years, and ≥65 years). At 1 month post-booster vaccination, across all age groups, >99.0% of participants were seroprotected against diphtheria and tetanus and >96.0% of participants were seropositive for anti-pertussis antibodies. For all antibodies across all age groups, antibody GMCs increased from pre- to 1 month post-booster vaccination and booster responses to diphtheria (in 71.5% of participants), tetanus (85.3%), and pertussis antigens (≥85.6%) were observed. One serious adverse event that was not causally related to the study vaccine was reported. No fatal cases were reported throughout the study period. In conclusion, administration of the dTpa vaccine as a booster dose in healthy Russian participants induced a robust immune response to all vaccine antigens and was generally well tolerated across all age groups.

Retrospective Study of the Clinical Epidemiological Characteristics of Pertussis in Infants Prior to Their First Vaccination in the Russian Federation.

INTRODUCTION: The coverage of pediatric pertussis vaccination in the Russian Federation is high, generally using a diphtheria, tetanus, and whole-cell pertussis vaccine in a 3-, 4.5-, and 6-month primary series and with a booster at 18 months of age. However, with no registered pertussis vaccines for adults, unvaccinated adolescents and adults can be a major source of infection of infants under 3 months of age. METHODS: A multicenter, retrospective, clinical epidemiological analysis to characterize pertussis in infants aged up to 3 months who contracted pertussis and were hospitalized in four different cities in the Russian Federation was performed. Archived medical records and a questionnaire were used to collect the relevant epidemiological and clinical aspects for each case of pertussis over a 2-year period. RESULTS: Infants in four different regions of the Russian Federation in the first 3 months of life, prior to their first pertussis vaccination, are at risk of pertussis infection. The severity is generally worse in neonates, and can lead to complications that can require intensive care. CONCLUSION: Prior to vaccination, young infants in the Russian Federation remain vulnerable to severe pertussis, which may be worsened by their proximity to unvaccinated adults.