Results from a recent study published in the journal Pediatrics show that the Gardasil 9 HPV vaccine can be used safely and effectively in girls and boys aged between 9 and 15 years. These results advance on previous studies, which have found identical results for girls and young women aged between 16 and 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, said in a recent news release. “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.”

A total of 3,066 people received three-dose of 9vHPV vaccine regimen, after which researchers conducted anti-HPV serologic assays. The team classified the cohort into three different groups: girls (aged 9 to 15 years); boys (aged 9 to 15 years); and women (aged 16 to 26 years).

Results revealed that following the final dose (at 4 weeks), more than 99% of girls, boys, and young women seroconverted for each HPV vaccine type. The results also showed an increase in geometric mean titers to HPV types 6/11/16/18/31/33/45/52/58. After 2.5 years of the initial dose, results showed that the anti-HPV response persisted.

The results indicated that the three-dose 9-valent HPV vaccine had a similar effect in girls and boys aged between 9 and 15 years. Furthermore, the 9-valent HPV vaccine series were well-tolerated in girls and boys with only a small proportion of girls (81.9%) and boys (72.8%) reporting injection-site mild to moderate adverse events.

“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 stated in the news release.

In the U.S., there are about 12,000 women diagnosed with cervical cancer every year, with roughly 4,000 dying as a consequence of the disease. Gardasil-9 has the potential to prevent many cancers caused by human papillomavirus (HPV) infections, including:

• cervical cancer in females,
• vaginal and vulvar cancers in females, and
• anal cancer in females and males.