Background: Prelicensure clinical studies may not include sufficient numbers of subjects to assess the potential for rare postvaccination adverse events. The aim of this postlicensure study (NCT00297856) was to evaluate uncommon outcomes following vaccination with a tetanus, reduced-antigen-content diphtheria, and acellular pertussis vaccine (Tdap, Boostrix GlaxoSmithKline) in a large adolescent cohort.
Methods: We monitored safety outcomes among 13,427 10 to 18-year-old adolescents enrolled in the Northern California Kaiser Permanente Health Care Plan who received Tdap vaccination as part of their normal health care. Subjects were evaluated using self-control analysis comparing days 0 to 29 to days 30 to 59 postvaccination for neurologic events, hematologic events and allergic reactions. We evaluated new onset chronic illnesses within 6 months of Tdap vaccination by comparing with historical Td controls matched for age at vaccination, season, sex, and geographic area. We also compared the incidence of events of interest between the Tdap and historical cohorts as exploratory analyses.
Results: No increased risk for medically attended neurologic (odds ratio [OR], 0.962; 95% confidence interval [CI], 0.533–1.733) or allergic reactions (OR, 1.091; 95% CI, 0.441–2.729) was observed following Tdap vaccination when comparing the first 30 postvaccination days to the second 30 postvaccination days. There was one hematologic event within 30 days of Tdap, compared with 0 events within days 30 to 59 (P = 1.0). When compared with matched historical Td recipients, no increase in new onset chronic illnesses (OR, 0.634; 95% CI, 0.475–0.840) was seen after Tdap. No deaths occurred in the Tdap cohort during the study.
Conclusions: This study provides no evidence for an increased risk for neurologic, hematologic, allergic events, or new onset of chronic illnesses among adolescents vaccinated with Tdap.
From the *Kaiser Permanente Vaccine Study Center, Oakland, CA; †Center for Global Health, Cincinnati Children's Hospital, Cincinnati, OH; and ‡GlaxoSmithKline Biologicals, King of Prussia, PA.
Accepted for publication December 29, 2009.
Research support by GlaxoSmithKline, Merck & Co.: GlaxoSmithKline Biologicals was the funding source and was involved in all stages of the study conduct and analysis. GSK Biologicals also funded all costs associated with the development and the publishing of the present manuscript. The corresponding author had full access to the data and was responsible for data analysis and manuscript submission. Supported by GlaxoSmithKline, Merck & Co., Sanofi Pasteur, Norvartis and Wyeth (to N.P.K.).
S. Black is a consultant for GlaxoSmithKline and Norvartis; W. Weston, S. Wu, P. Li, B. Howe, L.R. Friedland are all employees of GlaxoSmithKline.
Boostrix and Infanrix are trademarks of the GlaxoSmithKline group of companies. Menactra is a trademark of Sanofi-Pasteur.
Address for correspondence: Nicola P. Klein, MD, PhD, Kaiser Permanente Vaccine Study Center, 1 Kaiser Plaza, 16th floor, Oakland, CA 94612. E-mail: email@example.com.
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