The rate of insured girls and young women completing the three-dose series of the human papillomavirus (HPV) vaccine has significantly dropped since the vaccine was approved in 2006, according to a study published in the journal Cancer.
Of the 271,976 females included in the study, just 38.2 percent received all three doses within 2009. The steepest decline was found among girls ages 9 to 18, which researchers said is the age group that can receive the greatest benefit from the vaccine.
“The surprising finding is that the completion rates are going down over time among young girls,” said co-author Dr. Abbey B. Berenson. “We thought that with more knowledge coming out about the vaccine, people would be more likely to complete it instead of less likely.”
Among age groups, girls ages 9 to 12 were more likely to receive all three doses compared with their older counterparts. Still, the preteens’ rates dropped by more than half: In 2006, 57 percent completed the series, compared with 21 percent in 2009.
Just 23 percent of women 19 to 26 years old completed the series in 2009, compared with 44 percent in 2006. Among girls ages 13 to 18, the completion rate dropped by 34.1 percent.
Co-author Dr. Jacqueline M. Hirth said they weren’t able to determine exactly why the completion rates have dropped so drastically among teenagers, but the results show “a need to find ways to change these patterns.”
“It’s a very preliminary look at what’s going on in each population,” she said. “We don’t really know why this is, but it’s something we need to find out, especially because that population is the age group that needs to be targeted.”
Six years ago the Food and Drug Administration (FDA) approved the vaccine for its effectiveness in preventing HPV infection, which can lead to cervical cancer. According to the National Cancer Institute, there have been 12,170 cases of and 4,220 deaths from cervical cancer in the US so far this year. Each year, nearly a quarter million women die from it worldwide.
The vaccine also protects against genital warts and anal, penile, and some head and neck cancers. In 2009 the FDA also recommended that boys receive the HPV vaccine.
Previous recommendations said the vaccine should be administered within six months, but Berenson notes that recent data shows it’s still effective if all three doses are administered within a year.
Berenson and Hirth said they are currently working on examining the HPV vaccine completion rates of males.
The full study is available on the Wiley Online Library website.