Majority of those who receive the vaccine fail to get the recommended three doses
In a study of more than 9,600 adolescent and young adult women in the Baltimore area, researchers at the University of Maryland School of Medicine have found that fewer than 30 percent of those eligible to receive the human papillomavirus (HPV) vaccine to prevent cervical cancer actually chose to get it. And only about a third of those who began receiving the vaccine completed the three doses recommended for maximum protection.
The research, which was led by J. Kathleen Tracy, Ph.D., an assistant professor of epidemiology, will be presented on Nov. 9, 2010, at a cancer prevention research conference in Philadelphia sponsored by the American Association for Cancer Research.
"Despite strong evidence that the HPV vaccine is highly effective, our study showed that relatively few women choose to take it, and the majority of them don't complete the recommended series of doses," Dr. Tracy says. "This means that large numbers of these young women are unprotected or under-protected from strains of HPV that lead to cervical cancer."
HPV is the most common sexually transmitted disease among adolescent girls in the United States, with 29.5 percent of sexually active 14- to 19-year-olds infected at any given time. Persistent infection with certain strains of HPV has been shown to cause cervical cancer. Vaccines that target the most common strains of HPV have been licensed in the United States since 2006. Doctors recommend the vaccine for girls and young women from ages 12 to 26 years old, although girls as young as 9 years old can take it.
E. Albert Reece, M.D., Ph.D., M.B.A., vice president of medical affairs at the University of Maryland and dean of the University of Maryland School of Medicine, says, "HPV vaccines have the potential to greatly reduce and possibly even eliminate cervical cancer in those most at risk of developing it. However, these vaccines are only effective if young women choose to be vaccinated and receive the recommended dosage. Dr. Tracy's research raises significant public health concerns about whether this at-risk population is being adequately protected." Dr. Reece, a gynecologist, also notes that vaccination against HPV doesn't eliminate the need for annual cervical cancer screening.
The study was based on clinical data from the University of Maryland Medical Center's outpatient gynecology clinics, where 9,658 adolescent and young adult women, ages 9 to 26, who were potentially eligible for the vaccine were seen from August 2006 until August 2010. Of these, 2,641 young women, or 27.3 percent, started the vaccination process - 39.1 percent completed one dose, 30.1 percent completed two doses and 30.78 percent completed all three doses. Two-thirds of those who began taking the vaccine were African-American.
Young women, ages 18 to 26, were the least likely to complete more than a single dose of the vaccine. African-American women were less likely than young white women to complete all three doses, according to the research.
"We don't know why the young women in our study opted not to take the vaccine or failed to complete the three-dose regimen," says Dr. Tracy, who is a health psychologist. "But our research very clearly points out the need to develop strategies to encourage eligible women to take the vaccine as directed for maximum protection. Parents may have to take a more active role in making sure their daughters receive all the necessary doses."
Dr. Tracy notes that she and her University of Maryland colleagues are planning to conduct a small clinical trial to determine if sending patients text-message reminders might increase the number of people who complete the vaccination process. "We need to develop evidence-based interventions to foster increased participation in vaccine programs and eliminate barriers for young women, in particular, minority women," Dr. Tracy says.