Only about one in three young women has received the human papillomavirus (HPV) vaccine to help prevent cervical cancer, according to a new report from researchers at Washington University School of Medicine in St. Louis.
The findings are published in the May issue of the American Journal of Preventive Medicine.
The HPV vaccine prevents four strains of the sexually transmitted human papillomavirus, two of which are found in about 70 percent of all women with cervical cancer. Both the American Cancer Society and the Advisory Committee on Immunization Practices recommend that women and girls receive the vaccine, but the new data shows that only 34 percent of girls ages 13 to 17 were vaccinated in the six states surveyed.
"The good news is that the vaccination rate is increasing," says first author Sandi L. Pruitt, PhD. "The bad news is this is just the first dose of a three-dose vaccine."
Pruitt, a postdoctoral research associate in Washington University's Division of Health Behavior Research, tracked rates of HPV vaccination in Delaware, New York, Oklahoma, Pennsylvania, Texas and West Virginia. She and senior investigator Mario Schootman, PhD, analyzed data from 1,709 girls in 274 counties of the six states in this study. The information came from a national telephone survey called the Behavioral Risk Factor Surveillance System (BRFSS).
"This was the first year the survey asked about HPV vaccination," Pruitt says. "That portion of the survey was optional, and only six states opted to use it. Ideally, we'd like to know what's happening in more states, but these six states represent a good cross-section of urban and rural, rich and poor, and they do include girls from racial and ethnic groups that closely mirror the rest of the country."
More than 70 percent of the girls in this study were white, and almost 75 percent had health insurance. Girls living in states with more poverty were less likely to get the HPV vaccine, but higher poverty rates in the individual counties within those states and lower family income levels actually made it more likely a girl would be vaccinated. Pruitt says those seemingly contradictory findings may be explained in part by the way in which funding for vaccines is allocated.
"For the neediest children, the United States has a publicly funded vaccination system, but each state sets its own guidelines for who is eligible to receive free vaccines," she says. "Individual states set different guidelines for providing vaccines to those with no insurance versus those who may be underinsured. So girls from poorer counties may be more likely to qualify for a free vaccine, whereas those states with more poverty may not have adequate funding to provide it or may be less likely to fill in gaps for those who may not have enough private insurance coverage to pay for it."
Pruitt says it's important that poorer, less-educated African-American and Hispanic girls and women have access to the HPV vaccine because women from those groups have higher rates of cervical cancer. This study found women from those racial and ethnic backgrounds are just as likely as white girls to receive the initial dose of the vaccine.
"We didn't find a racial disparity in terms of vaccination," she says. "That's very important because the highest burden of cervical cancer is among women of color, especially Hispanic women and those who live along the U.S.-Mexico border. There's a huge epidemic of cervical cancer among those women, so the fact that we didn't find racial and ethnic disparities is a good thing."
Last year, an estimated 11,000 cases of cervical cancer were diagnosed in the United States, and more than 4,000 of those women will eventually die from the disease.
Girls whose parents had more education also were more likely to get the vaccine, but surprisingly, rates of vaccination declined slightly as family income levels rose. Pruitt says that may be due to the rising number of wealthier parents choosing not to vaccinate their children for anything, but it's unclear from the data what motivated people to choose either to vaccinate or not.
The HPV vaccine, known as Gardasil, was controversial when it was approved by the U.S. Food and Drug Administration in 2006 because some feared that vaccinating girls as young as age 11 against a sexually transmitted virus may encourage them to become sexually active or engage in riskier behaviors. But no evidence to date suggests receiving the HPV vaccine encourages earlier sexual initiation or riskier sexual behaviors.
The vaccine is now approved for both boys and girls, beginning at age 11 to 12. The HPV vaccine also can be given to adolescents and young adults as old as 26. Pruitt says as more states report on the HPV vaccine, it will be possible to learn whether to anticipate future reductions in the incidence of cervical cancer.
Pruitt SL, Schootman M, Geographic disparity, area poverty and human papillomavirus vaccination. American Journal of Preventive Medicine, vol. 30 (5), pp. 525-533. May 2010.