June 24, 2015 — The human papillomavirus 9-valent vaccine is as effective and as safe for children and adolescents as it is for young women, according to the results of a small study published in the journal Pediatrics, MedPage Today reports.
The study divided participants into three groups: boys ages nine to 15, girls ages nine to 15 and young women ages 16 to 26. Study participants were given doses of the 9-valent HPV vaccine at day one, month two and month six.
The girls and boys who participated in the study were "generally healthy and sexually naïve" at the time of enrollment and throughout the six-month vaccination period, according to the study. Meanwhile, the young women who participated in the study had no abnormal Pap tests or cervical biopsy results, as well as no more than four sexual partners during their lifetimes. According to the study,"[n]early one quarter (22.7%) of young women were PCR-positive at enrollment, and at day [one], 40.9% of those women were positive for at least one HPV type by serology or PCR," MedPage Today reports.
According to the study authors, the study was the first to compare the 9-valent vaccine's effectiveness in children with its effectiveness in young women. The study included 3,066 participants at 72 sites across 17 countries from 2009 to 2013.
The study found that after girls and boys ages nine to 15 and young women ages 16 to 26 had an equivalent increase in anti-HPV geometric mean titers, or GMTs, four weeks after all the groups received their final dose.
Further, the study found more than 99% of girls and boys ages nine to 15 and more than 99% of young women seroconverted for all nine HPV types. In addition, 2.5 years after their third vaccine dose, more than 90% of girls and boys tested seropositive.
According to the study, adverse events at the vaccination site were reported more in young women, at 85.4%, than in girls, at 81.9%, or boys, at 72.8%. Young women most frequently reported adverse events such as erythema, pain, pruritus and swelling, while boys and girls most frequently reported fever and pyrexia. There were two serious adverse events reported that led to hospitalizations.
Joseph Kurland -- a vaccine specialist at Children's Hospitals and Clinics of Minnesota, who was not involved with the study -- said children should receive HPV vaccines before possible exposure since the disease is so widespread. He noted, "Waiting to vaccinate until after sexual activity has started is like buying a helmet for a child only after they learn to ride a bike. While they may not get into a serious crash or hit their head, withholding protection puts them at unnecessary risk" (Walker, MedPage Today, 6/22).