(HealthDay News) — For 11–15-year olds, concomitant administration of Gardasil 9 (9-valent human papillomavirus [9vHPV] vaccine) and Menactra (MCV4; Neisseria meningitides serotypes A/C/Y/W-135) or Adacel (Tdap; diphtheria/tetanus/acellular pertussis) is noninferior to intermittent administration, according to a study published online August 3 in Pediatrics.
Andrea Schilling, MD, from Alemana-Universidad del Desarrollo in Santiago, Chile, and colleagues compared the immunogenicity and safety of 9vHPV administered concomitantly or nonconcomitantly with MCV4 and Tdap in 11–15-year-old boys and girls. Participants received 9vHPV at day one and months two and six; MCV4/Tdap was administered concomitantly with 9vHPV vaccine at day one in the concomitant group (621 children); MCV/Tdap was received at month one in the nonconcomitant group (620 children).
The researchers found that the concomitant group was noninferior to the nonconcomitant group in terms of the following: geometric mean titers for all HPV types in 9vHPV vaccine four weeks after dose three; the proportion of subjects with a four-fold increase or greater in titers for four N. meningitides serotypes four weeks after MCV4 injection; the proportion of individuals with antibody titers to diphtheria and tetanus ≥0.1IU/mL; and geometric mean titers for pertussis antigens four weeks after Tdap injection. The concomitant group had more frequent injection-site swelling. No vaccine-related serious adverse events were reported.
“Concomitant administration of 9vHPV vaccine with MCV4/Tdap was generally well tolerated and did not interfere with the antibody response to any of these vaccines,” the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including Merck, which manufactures Gardasil 9 and funded the study.