Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States. There are 14 million new infections each year, which can lead to six different types of cancers.

While an HPV vaccine became available over 10 years ago, a study led by the Yale School of Public Health finds that there is “substantial” room for improvement in the way it is recommended and discussed. The number of adolescents—the target population—in the United States getting vaccinated remains low, with only 42 percent of adolescent females and 28 percent of adolescent males having received the three-dose immunization regimen.

The study, published in the journal Qualitative Health Research, found that:

Many parents of unvaccinated children hadn’t discussed the vaccine with health care providers or had low levels of vaccine awareness.Among vaccine-unaware parents, receiving even brief information about the HPV vaccine generally resulted in increased enthusiasm about the precautionary step.

Parents also had low awareness of the three-dose regimen, poor recall about whether their child had received all three doses, and little understanding of why boys should be vaccinated, the study found

“These findings clearly point to the very important role that health care providers can play in increasing coverage with this safe and effective vaccine,” said lead author Linda M. Niccolai, Ph.D., associate professor in the school’s Department of Epidemiology of Microbial Diseases and member of the Cancer Prevention and Control Program of the Yale Cancer Center. “We really need to work more with providers to ensure that all eligible adolescents receive strong, urgent, and consistent recommendation for HPV vaccination.”

The rate of vaccination for HPV is lower than for other vaccines recommended for adolescents, including tetanus, diphtheria, pertussis and meningococcal disease. Rates also lag behind other industrialized nations. Adolescent females in Australia, Denmark and England (countries with national HPV immunization programs) have more than 70 percent participation.

Niccolai and her research colleagues used in-depth interviews to learn how participants experience and interpret HPV vaccination visits with their children. They found that some parents believe the vaccine wasn’t needed, or they had concerns about vaccine safety or efficacy. Health care providers can help to increase understanding of these topics. There is abundant data that HPV vaccines are both highly effective and very safe. The vaccines are currently recommended by the CDC’s Advisory Committee on Immunization Practices, the American Academy of Pediatrics, and several other professional organizations, Niccolai said.

“Unfortunately, after more than a decade of vaccine availability in the United States, vaccination rates have stagnated,” said Niccolai. “We need to come up with new ways for providers to communicate the importance of this vaccine to our patients.”

The study was coauthored by Caitlin Hansen, M.D., associate research scientist, and Professor Eugene Shapiro, M.D., both of the Yale School of Medicine.