Safety of reduced-antigen-content tetanus-diphtheria-acellular pertussis vaccine in adolescents as a sixth consecutive dose of acellular pertussis-containing vaccine.

Abstract:  OBJECTIVE: The safety of a booster dose of a reduced-antigen-cont ent tetanus-diphtheria-a cellular pertussis (Tdap) vaccine was evaluated in adolescents previously vaccinated with five doses of acellular pertussis-containing vaccine. STUDY DESIGN: Adolescents (n = 319) previously vaccinated with either 5 doses of diphtheria-tetanus-a cellular pertussis (DTaP) (n = 193) or 4 doses of DTaP plus another acellular pertussis-containing vaccine received one dose each of Tdap and hepatitis A vaccine in a double-blinded, randomized, crossover trial. Rates of adverse events (AEs) after vaccination with Tdap versus hepatitis A and rates of local AEs among adolescents vaccinated with Tdap (sixth acellular pertussis-containing vaccine dose) versus rates in these same individuals after vaccination with their fifth DTaP dose were assessed. RESULTS: After Tdap, pain (63.6%), redness (51.7%), and swelling (41.4%) were the most frequently reported AEs. Large injection site swelling (swelling > 100 mm, arm circumference increase > 50 mm or diffuse swelling interfering with daily activities) occurred in three adolescents and resolved without sequelae. After the sixth dose of acellular pertussis-containing vaccine, adolescents reported more pain and less redness and swelling compared with incidences of these AEs reported when these same individuals received their fifth DTaP dose. CONCLUSIONS: These results suggest that Tdap is well tolerated as a sixth consecutive dose of acellular pertussis-containing vaccine.