Recent study data showed that Gardasil 9 HPV vaccine also is safe and effective in boys and girls aged 9 to 15 years, advancing previous research that found similar results for girls and young women aged 16 to 26 years.
“This study represents the first analysis of 9-valent HPV vaccine immunogenicity in girls and boys 9 to 15 years of age, the primary target population for immunoprophylaxis to prevent HPV-related pre-cancers and cancers of the anogenital tract,” researcher Pierre Van Damme, MD, PhD, of the Center for the Evaluation of Vaccination, University of Antwerp, and colleagues wrote. “The antibody responses in 9- to 15-year-old boys and girls was shown to be noninferior to those observed in 16- to 26-year-old young women.”
The researchers included 3,074 vaccine recipients from more than 72 worldwide sites. The cohort was classified into three groups: girls, aged 9 to 15 years; boys, aged 9 to 15 years; and women, aged 16 to 26 years. All participants were administered the three-dose Gardasil 9 (9vHPV, Merck) vaccine series, with the second dose given at month 2 and the third does given at month 6. The study was conducted between August 2009 and April 2013.
At 4 weeks after the final dose, more than 99% of all vaccine recipients seroconverted for each vaccine HPV type (6/11/16/18/31/33/45/52/58). Further, anti-HPV response remained persistent at 2.5 years after the initial dose. These findings suggested that the three-dose, 9-valent HPV vaccine is equally as effective in boys and girls aged 9 to 15 years.
Van Damme and colleagues also found the 9-valent HPV vaccine series was well-tolerated in boys and girls, with a lower percentage of girls (81.9%) and boys (72.8%) than young women (85.4%) reporting adverse events associated with the injection site. The most common adverse events were mild to moderate pain, swelling, erythema, and pruritus. Only two cases of vaccine-related serious adverse events were observed during the study.
“These data support bridging the efficacy findings with 9-valent HPV vaccine in young women 16 to 26 years of age to girls and boys 9 to 15 years of age and implementing gender-neutral HPV vaccination programs in preadolescents and adolescents,” Van Damme and colleagues wrote. – by David Costill
Disclosure: Van Damme reports receiving speakers fees for presentations on vaccines that are paid directly to an educational fund held by the University of Antwerp. Please see the full study for a list of all other authors’ relevant financial disclosures.