Nov. 9, 2010 -- Just one-third of teenage girls actually complete all three required doses of the human papillomavirus (HPV) shot, suggesting that many teens are unprotected or underprotected from the strains of HPV linked to cervical cancer. These findings will be presented at the American Association for Cancer Research annual meeting in Philadelphia.
The HPV shot protects females against the types of HPV that cause most cervical cancers. The CDC recommends the shot for girls and young women aged 11 to 26. Two HPV vaccines are licensed by the FDA and recommended by the CDC: Cervarix and Gardasil. The Gardasil vaccine also protects against most genital warts. Both vaccines require three doses for maximum protection.
"I was surprised by the relatively poor completion rate," says study researcher J. Kathleen Tracy, PhD, an assistant professor of epidemiology and public health at the University of Maryland School of Medicine in Baltimore.
"Making another trip back to the doctor is a barrier to following through, and having to do it three times is an even bigger barrier."
In the new study of more than 9,600 adolescent and young adult women who were seen between August 2006 and August 2010, 27.3% started the vaccine process. Slightly more than 39% received one shot, 30.1% received two doses, and 30.78% received all three required doses, the study shows.
Particularly at risk for not completing the HPV vaccine series were young women aged 18 and older and young black women and teens.
"Eighteen-year-olds are more likely to be transient and more likely be in between home and college, and this is the first time mom or dad isn't telling you 'don’t forget to go and get this,'" she tells WebMD.
HPV Shot Controversy
There has also been controversy about mandating the HPV shot, which could play a role in the low rates of vaccine acceptance and completion.
"HPV is not a disease in the way that the flu, measles, and mumps are, and parents didn't like being told it was mandated," she says. "Most parents also don't want to think about [9-year-olds] as sexual beings either." The vaccine is licensed for use in girls as young as 9.
In a related report, Sarah E. Gollust, PhD, an assistant professor in the division of health policy and management at the University of Minnesota in Minneapolis, and colleagues found that people were less likely to support laws requiring the HPV vaccine for young girls when they learned that there is political and medical controversy over such laws. These findings appear in the November issue of the journal Health Affairs.
"We know that HPV vaccine mandates have been hotly debated in the U.S. news media, with medical and public health experts, politicians, and others disagreeing about whether the HPV vaccine should be required for girls [and] our study showed that exposure to this controversy made people more wary of supporting laws requiring the vaccine," she says in an email.