Targeting the human papillomavirus (HPV) vaccine to sexually active young adult women at greatest risk for contracting one or more of the HPV strains known to cause cervical cancer and genital warts might seem like an effective strategy.
A new study, however, from researchers at the C.S. Mott Children’s Hospital’s Child Health Evaluation and Research (CHEAR) Unit finds that using certain risk factors, including sexual history, to determine if a woman should be vaccinated could deprive more than 80 percent of eligible women from getting the vaccine.
The research, published in the Feb. 20 issue of Vaccine, reveals that such an approach instead likely would vaccinate a large number of women already infected with at least one of the four HPV strains the vaccination provides protection against, says study lead author Dr. Amanda Dempsey, a member of the CHEAR Unit team in the Division of General Pediatrics at C.S. Mott Children’s Hospital.
“Selectively vaccinating women based on risk factors alone would mean that more than 2 million women, ages 18 to 26, who had the potential to derive the most benefit from HPV vaccination because they weren’t already infected, would miss out on getting the vaccine,” Dempsey says.
According to study results, behavioral risk factors should not be used by health care providers to determine if a young woman should be vaccinated. There were a lot of women in the study without certain risk factors that still had HPV, Dempsey says.
Much of the confusion over whether or not to vaccinate a patient stems from conflicting vaccination recommendations. The American Cancer Society advocates vaccinating all females younger than 18, and selectively vaccinating women ages 19 to 26 based on an informed discussion between the patient and her doctor about sexual history. The Centers for Disease Control and Prevention’s Advisory Committee on Immunizations Practices, however, recommends universal vaccination for all women ages 11 to 26, regardless of sexual experience.
The HPV vaccine is the most expensive routinely recommended vaccine. Financial barriers — underinsurance, no insurance, lack of state or federal vaccine financing — can make it difficult to provide the vaccine to all eligible females, Dempsey says.
Combined, these issues raise the question of whether or not a targeted approach to HPV vaccination among sexually active young women would be a better option than a comprehensive, universal vaccination strategy.
Using data from the National Longitudinal Study of Adolescent Health, Dempsey and her colleagues worked to test the effectiveness of a targeted approach to vaccination. They evaluated how well certain risk factors correlate with having HPV, as well as what would happen if behavioral risk factors were used as a way to target the vaccine to only certain groups of women.
Among the study’s 3,276 women, ages 19 to 24, more than 9 percent had at least one of the four HPV types that the vaccine protects against. When evaluated for all 27 HPV types, the prevalence of HPV infection grew to more than 26 percent among the study group.
Women with certain risk factors — an older sex partner, more than three lifetime sex partners, a new sex partner within the past year and use of illegal drugs within the past year — were more likely to have an HPV vaccine-type infection.
In addition to Dempsey, the study was co-authored by Achamyeleh Gebremariam, with the CHEAR Unit in the Department of Pediatrics at the Health System.
