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

OBJECTIVE

The safety of a booster dose of a reduced-antigen-content tetanus-diphtheria-acellular 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-acellular 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.