News Release

Photo: For a photo of Brewer, click on http://www.unc.edu/~ntbrewer/

HPV vaccine does not lead adolescent girls to have more sex, most parents agree

CHAPEL HILL – Adolescent girls who are vaccinated against human papillomavirus (HPV), a sexually transmitted virus that may cause cervical cancer, are not likely to engage in sex more often than adolescent girls who are not vaccinated, according to a study led by a researcher from the University of North Carolina at Chapel Hill School of Public Health.

Another study by the same researcher shows that only about one in ten parents are concerned that vaccinating their children against HPV will encourage them to have more sex. The studies were published in the June 2007 journals Annals of Behavioral Medicine and Preventive Medicine.

Last year, the Food and Drug Administration approved the HPV vaccine Gardasil for use in females 9 to 26 years old. The approval launched intense debate about inoculating young women against a virus transmitted by sexual contact. 

“One of the main arguments against vaccinating young women for HPV is that they will somehow compensate for the vaccine's protective nature by having more sex,” said Noel T. Brewer, Ph.D., assistant professor of health behavior and health education at the UNC School of Public Health, who led both studies.  “Our findings say otherwise.”

To understand how the HPV vaccine may affect sexual behavior, Brewer and his co-authors studied Lyme disease prevention among individuals who received the vaccine for the tick-borne disease.  Brewer said the Lyme disease vaccine is a strong test of how risk perception affects behavior.

The researchers surveyed a random sample of 705 adults in northeastern U.S. areas with high Lyme disease incidence about what protective behaviors they engaged in, such as using tick repellent and wearing light colored clothing, before and after they were vaccinated. The researchers found vaccinated respondents were less likely to continue using one of five protective measures after vaccination, but the frequency of those measures did not dip below that among unvaccinated respondents.

“We found no evidence of disinhibition, where people started taking greater risks than the general population,” Brewer said.

To evaluate parents’ views, Brewer and Karah I. Fazekas, a UNC School of Public Health graduate, reviewed 28 studies on predictors of HPV vaccine acceptance.  They found that only six to 12 percent of parents are concerned that their children will have more sex once they are vaccinated.

“For parents, more important considerations for wanting to get the HPV vaccine are a doctor's recommendation, feeling at risk for cervical cancer and believing that the vaccine is safe and effective,” said Brewer. “Most Americans think adolescent girls should get the vaccine.”

Brewer said that the findings of the two studies should free policymakers from concerns that their constituents would oppose adopting the HPV vaccine, or that mandating the vaccine would actually lead to more risky sexual behaviors among adolescents. Instead, health officials should focus on ensuring HPV vaccine uptake in women at higher risk of developing cervical cancer. 

Study co-authors include James E. Herrington, Ph.D., director of the Division of International Relations at the National Institutes of Health; Cara L. Cuite, research project manager at the Cook Food Policy Institute at Rutgers University; and Neil D. Weinstein, emeritus professor of human ecology at Rutgers University.

Note: Brewer can be reached at ntba@unc.edu.

Web site: http://www.cdc.gov/std/hpv/STDFact-HPV-vaccine.htm

School of Public Health contact: Ramona DuBose, (919) 966-7467 or ramona_dubose@unc.edu
News Services contact: Becky Oskin, (919) 962-8596 or becky_oskin@unc.edu