Mothers less likely to pursue HPV vaccination for youngest daughters

Apr 30 2008

Because the first national study of its kind has found that U.S. mothers report they are less likely to vaccinate daughters under age 13 against human papillomavirus virus (HPV), even though the vaccine is recommended for girls at age 11 and 12, it's incumbent upon the healthcare community to work to improve moms' acceptance of the vaccination for younger daughters, say researchers at Cincinnati Children's Hospital Medical Center who conducted the study. HPV is a sexually transmitted virus known to cause cervical cancer.

The study will be presented May 4 at the American Academy of Pediatrics Presidential Plenary session, of the annual meeting of the Pediatric Academic Societies in Honolulu.

"Because HPV is the most common sexually transmitted infection (see background information below) and often acquired soon after the onset of sexual activity, the CDC recommends that HPV vaccination ideally occur before a girl becomes sexually active, as the vaccine will not reverse HPV infection," says Jessica Kahn, M.D., a physician in the division of adolescent medicine at Cincinnati Children's and the study's lead author. Currently the U.S. Centers for Disease Control and Prevention (CDC) recommends that 11- and 12-year-old girls be targeted for HPV immunization. But the researchers found that mothers surveyed are currently not inclined to follow that guideline.

In the study, while 86 percent of moms intended to vaccinate a 16- to 18-year-old daughter, and 68 percent intended to vaccinate a 13- to 15-year-old daughter, fewer than half -- only 48 percent -- intended to vaccinate a 9- to 12-year-old daughter, according to the data analyzed by Dr. Kahn and her colleagues. "Mothers' intention to vaccinate against HPV is lowest for the younger daughters. Yet, younger girls are more likely than older girls to benefit from vaccination, which is why the CDC recommends that they be targeted for vaccination. This discrepancy between mothers' attitudes and CDC recommendations represents a challenge for health care providers."

"We found that mothers' beliefs about HPV vaccination are the most powerful determinants of whether they intend to vaccinate their daughters at this age. The findings of our study, in combination with results of the evolving literature on HPV vaccine acceptability, provide information that can be used to improve moms' acceptance of HPV vaccination for their younger daughters."

Factors independently associated with intention to vaccinate a younger daughter included belief that one's daughter should get a regular Pap screen and beliefs about HPV vaccines. The seven-item scale measuring beliefs about HPV vaccines included perceived benefits to HPV vaccination (such as whether that vaccination will protect one's daughter against cervical cancer), perceived barriers to vaccination (such as whether that vaccination may lead to riskier sexual behaviors), belief that the daughter is at risk for HPV infection, belief that HPV-related diseases such as cervical cancer are serious, and belief that one's doctor would recommend vaccination.

Dr. Kahn said that the most powerful individual predictors that were most associated with likelihood to vaccinate their younger daughters were (in order): belief that HPV vaccination would provide protection against cervical cancer, belief that vaccinated girls would not practice riskier sex, belief that one's daughter's clinician would recommend HPV vaccines for her, and belief that one's daughter is at risk for HPV infection.

"Because we found moms' personal beliefs play such an important role in their decisions to have younger daughters immunized against HPV, the development of evidence-based messages that emphasize adolescent girls' risk for HPV infection, the effectiveness of the vaccine in preventing cervical cancer, and clinician endorsement of vaccination may increase the acceptability of the HPV vaccine among parents and help to maximize HPV vaccine uptake," says Dr. Kahn. "A comprehensive approach to enhancing parental acceptability of HPV vaccination would involve the combined efforts of clinicians, health educators, advocacy groups, and public health personnel."

For the study, Dr. Kahn and her colleagues surveyed 10,521 mothers of adolescents enrolled in the Growing Up Today Study (GUTS), a longitudinal study of the children of mothers participating in the Nurses Health Study II (NHS 2), between June 2006 and February 2007. The survey assessed demographic factors, gynecologic history, communication with daughters about Pap screening, and mothers' beliefs about Pap testing and about HPV vaccines as well as intention to vaccinate daughters of varying ages. Researchers also looked at mothers' intention to get the vaccine themselves and found that 48 percent intend to be vaccinated.

Dr. Kahn's study was funded by the American Cancer Society and included researchers from Indiana University, the University of Texas Medical Branch Galveston and Harvard University Medical School. The senior author was Lindsay Frazier, M.D., Children's Hospital Boston.

The PAS meeting is the largest international meeting focused on research in child health. It is sponsored by the American Academy of Pediatrics, the American Pediatric Society, the Society for Pediatric Research, and the Ambulatory Pediatric Association.

BACKGROUND ON HPV: An estimated 6.2 million people 14 to 44 years old are newly infected with HPV each year in the United States, and of these infections, 74 percent occur among those 15 to 24 years old, according to the CDC. Infection with one of the more than 100 types of HPV usually causes no symptoms and resolves on its own, but a proportion of women infected with specific cancer-associated types may develop cervical cancer. Two of these types, 16 and 18, cause about 70 percent of cervical cancers in women. Two other types, 6 and 11, cause about 90 percent of genital warts. The CDC estimates that 11,100 new cervical cancer cases were diagnosed in 2007 and approximately 3,700 women died from cervical cancer in the U.S. Health care professionals use the Pap test to screen for cervical cancer.

In June 2006, the U.S. Food and Drug Administration approved a vaccine against four types of HPV, 6, 11, 16 and 18, based on data from clinical trials indicating that the vaccine was highly effective in preventing persistent infection with these strains and subsequent cervical cancer precursor lesions, vaginal and vulvar cancer precursor lesions and genital warts. The FDA approved the HPV vaccine for use in U.S. women aged 9 to 26 years.