Ever since Gardasil was approved six years ago to combat various strains of the human papillomavirus, or HPV, which can lead to cervical cancer, some parents and social conservatives have worried the vaccine would be seen as a green light for teenage girls to engage in promiscuous sex. But a study finds the Merck vaccine is not associated with promiscuity, at least not among 11- and 12-year-old girls.
The study is apparently the first to evaluate changes in sexual activity and related outcomes - such as sexually transmitted infections, pregnancy or contraceptive counseling - after vaccination while also avoiding the risk of bias that may occur in sexual activity surveys relying on self-reported responses.
The study examined data from Kaiser Permanente Georgia involving 1,398 girls, including 493 were who given at least one of three doses of Gardasil and 905 who were not vaccinated. They found there was no statistically significant increased risk in sexual activity or related outcomes, including testing for pregnancy or sexually transmitted infections, between the groups.
"If HPV vaccination was 'a license for sex,' we would have expected to see more adverse outcomes shortly after vaccination, when the girls were more aware of their recent vaccination status," the authors write. They noted, though, that "most health care decisions for girls age 11 through 12 are made by parents or guardians, and it is not likely that perceptions of sexuality led at these ages to the decision to receive the HPV vaccine."
Although some may question the extent to girls at these ages are sexually active, the authors cite previous research indicating about 3 percent of high school girls reported initiating sexual activity before turning 13. They also point to data showing a "high prevalance" of adolescent genital HPV infection, with 33 percent of 14- to 19-year-olds infected with at least one HPV strain, and 12 percent infected with one of the four quadrivalent vaccine strains.
The data reviewed comprised vaccinations that took place during the first 18 months after Gardasil became available and the follow-up period lasted years, or through December 31, 2010. The vaccine was initially approved for females between the ages of 9 to 26, and approval was expanded in 2009 to boys and men for preventing genital warts caused by certain types of HPV (here is the study).
The results are likely to further fuel debate over HPV vaccines - GlaxoSmithKline markets Cervarix - which have been controversial for various reasons, including an ill-fated effort by Merck to surreptitiously lobby state governments for mandatory vaccination and lingering questions over serious side effects.
These issues briefly figured in the Republican presidential primary campaign last year, especially remarks made by Minnesota Congresswoman Michelle Bachman that Gardasil may be linked to mental retardation (read here). Earlier this month, in fact, a study funded by Merck declared Gardasil is safe, although a Gardasil researcher continues to express skepticism (see here).
Concerns about promiscuity were also cited as a key argument in an unsuccessful effort last year to block a California bill that removed parental consent for vaccinating children 12 and older against sexually transmitted diseases. The campaign was led, in part, by conservative groups (read here).
Earlier this year, a study reached a conclusion that offered something for each point of view – most adolescents perceived a need for safer sexual behavior after the first HPV vaccination. But at the same time, nearly 24 percent believed they were less at risk for getting a sexually transmitted disease after vaccination, according to our earlier report.
The study, which was published the Archives of Pediatric & Adolescent Medicine, queried 339 girls between the ages of 13 to 21 about their views on sexual risks after their first HPV vaccination. The authors concluded “education about HPV vaccines and encouraging communication between girls and their mothers may prevent misperceptions among these adolescents.” In other words, some teenagers may misconstrue the risks and more education is needed (back story).
vaccine pic thx to lulu on flickr