New report underscores HPV prevalence in U.S.
New report underscores HPV prevalence in U.S.
About one in four U.S. females between the ages of 14 and 59 may have human papillomavirus (HPV), according to results of the first national estimate of the infection.1
HPV is the most common sexually transmitted infection in the United States, and at least 50% of sexually active women and men acquire genital HPV infection at some point in their lives.2 While most HPV infections clear on their own, some high-risk types that do not can lead to cervical cancer in women. The American Cancer Society estimates there will be about 11,150 cases of cervical cancer in the United States in 2007, and about 3,670 women will die from the disease.3
The new research is the first nationally representative study of HPV among women with a broad age range, says Eileen Dunne, MD, MPH, a medical officer in the Centers for Disease Control and Prevention's (CDC) National Center for HIV, Viral Hepatitis, STDs, and Tuberculosis Prevention. The research findings indicate a high overall prevalence of HPV infection among females, especially among young women, notes Dunne, lead author of the analysis. Overall, more than one in four women (26.8%, or 24.9 million females) in the United States are infected with at least one type of HPV; almost half of women aged 20-24 are infected, she notes.
These baseline data will allow for future evaluations to monitor changes in prevalence, which would result as an impact of the HPV vaccine, says Dunne. The data also are useful for models on vaccine impact and cost-effectiveness, she states. "The findings also underscore the importance of STD prevention efforts and continued Pap screening to protect women's health."
Review the analysis
CDC researchers and colleagues were able to estimate the prevalence numbers by performing HPV DNA testing on 2,026 self-collected vaginal swabs from women ages 14-59 years who participated in the 2003-2004 cycle of the National Health and Nutrition Examination Survey.
Drawing from 1,921 adequate specimens, analysis showed that 26.8% of the women were positive for any HPV DNA. Researchers then used 2000 U.S. census data to extrapolate the prevalence rate to the population, estimating that approximately 24.9 million females in this age range have prevalent HPV infection.1 According to the researchers' calculations, prevalence of any HPV infection was highest among females ages 20-24 (44.8%); overall HPV prevalence among women ages 14-24 was 33.8%.
According to the researchers' analysis, there was a significant trend for increasing HPV prevalence with each year of age from 14 to 24 years, followed by a gradual decline in HPV prevalence through age 59. Independent risk factors for HPV detection were age, marital status, and increasing numbers of lifetime and recent sex partners. Overall, HPV types 6, 11, 16, or 18 were detected in 3.4% of the study participants, corresponding with 3.1 million women with prevalent infection in the general U.S. population.
Who gets immunized?
The CDC's Advisory Committee on Immunization Practices has recommended the HPV vaccine for adolescent girls ages 11-12, with catch-up vaccination for those between ages 13 and 26.
According to an accompanying editorial to the new CDC research, more information is needed about the prevalence of HPV-16/18 in women older than age 26 to help determine whether women in this age group would benefit from immunization.4 Such studies are important not only to evaluate the HPV vaccine's effectiveness, but also to determine whether other high-risk HPV types will fill the ecological niche created by the expected decline in HPV-16 and HPV-18, the editorial states.4 Editorial co-author Susan Weller, PhD, professor of preventive medicine and community health at the University of Texas Medical Branch in Galveston, says, "What we would really like to see is good baseline data, [perhaps] estimates of the oncogenic types and specifically 16/18, for each age group."
Studies of cost-effectiveness of the vaccine have used HPV prevalence estimates from selected populations, including some outside the United States.5-7 Researchers will need to assess the cost-effectiveness of the HPV vaccine using the new prevalence data, the editorial states.
The best time to get the HPV vaccine is before sexual debut, says Susan Wysocki, RNC, NP, FAANP, president and chief executive officer of the National Association of Nurse Practitioners in Women's Health. However, since many family planning providers do not see women until after they are sexually active, they also should keep in mind that the data from the clinical trials demonstrate that most women have not been infected with all four of the HPV types that are covered in the vaccine that is currently available, so most will still benefit from the vaccine, she notes.
"We have a great opportunity to educate the women seen in family planning clinics who have young daughters," states Wysocki. "We have opportunities to make a difference with both the sexually active young women in the 'catch-up' group, as well as young women before sexual debut, through educating their mothers."
References
- Dunne EF, Unger ER, Sternberg M, et al. Prevalence of HPV infection among females in the United States. JAMA 2007; 297:813-819.
- Centers for Disease Control and Prevention. Genital HPV Infection. Fact sheet. Accessed at: www.cdc.gov/std/HPV/STDFact-HPV.htm.
- American Cancer Society. Cancer Facts & Figures 2007. Atlanta: American Cancer Society; 2007.
- Weller SC, Stanberry LR. Estimating the population prevalence of HPV. JAMA 2007; 297:876-878.
- Goldie SJ, Kohli M, Grima D, et al. Projected clinical benefits and cost effectiveness of a human papillomavirus 16/18 vaccine. J Natl Cancer Inst 2004; 96:604-615.
- Schlecht NF, Kulaga S, Robitaille J, et al. Persistent human papillomavirus infection as a predictor of cervical intraepithelial neoplasia. JAMA 2001; 286:3,106-3,114.
- Rousseau MC, Pereira JS, Prado JC, et al. Cervical coinfection with human papillomavirus (HPV) types as a predictor of acquisition and persistence of HPV infection. J Infect Dis 2001; 184:1,508-1,517.
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