Research looks at spread of genital warts
Research looks at spread of genital warts
The teenager in front of you says she has some bumps on her genital area. A closer inspection shows several flesh-colored, flat growths on her vulva. What's your next move?
If you suspect genital warts caused by human papillomavirus (HPV) infection, don't be surprised. Also called condylomata acuminata, genital warts are a common sexually transmitted disease (STD) caused by specific types of HPV. About 6% of U.S. adults have been diagnosed with genital warts, findings from a new report indicate.1
It is estimated that approximately 1% of sexually active adults in the United States has genital warts at any one time; however, prior to this new research, there were no nationally representative data on genital warts, says Thu-Ha Dinh, MD, MS, a medical epidemiologist with the Centers for Disease Control and Prevention's (CDC) Division of STD Prevention.
"Using data from the National Health and Nutrition Examination Survey, we determined the percentage of sexually active persons ages 18 to 59 years who reported having a history of genital warts diagnosed by a health care provider and identified key factors associated with a reported history of genital warts in this population," says Dinh, who served as lead author of the report. "The CDC is committed to working to get a better picture of the impact of STDs on Americans; this study contributes another vital piece to that picture."
Review the research
In performing the analysis, researchers reviewed responses from nearly 11,000 sexually active men and women, ages 18 to 59, who provided information on their sexual behavior and medical history, including whether a doctor had ever told them they had genital warts.
Overall, 5.6% of adults surveyed had been diagnosed with genital warts, researchers found. The rate was three times higher in women, after adjustment for other factors. Researchers are uncertain whether this finding reflected a true difference in risk or was related to other factors, such as differences in the recognition or diagnosis of warts.1
The prevalence of genital warts was highest (10.5%) among women ages 25-34. In men, prevalence peaked at 6% between the ages of 35 and 44. Risk was also higher among non-Hispanic whites, compared to Hispanics and blacks.
What was the main risk factor for genital warts? Findings indicate the leading cause was number of sex partners: Risk for infection was nearly eight times higher for adults with more than 10 lifetime partners, compared to those with one to two partners.1
Shot offers protection
The new report provides a "critical piece of information" about the impact of HPV-related diseases in the United States, states an accompanying editorial.2 While many studies have looked at the burden of cervical cancer and precancerous lesions caused by HPV infection, there has been little information about the rates, costs, and impact of genital warts, it states.2
The HPV vaccine Gardasil (Merck & Co.; Whitehouse Station, NJ) protects against four HPV types, which together cause 70% of cervical cancers and 90% of genital warts. "Because the HPV vaccine currently licensed in the U.S. provides protection against genital warts and cervical cancer, understanding the national burden of genital warts is critical to being able to evaluate the population-level impact of national HPV vaccination campaigns," the editorial states.
According to Merck, about 13 million doses of the vaccine have been distributed globally since its approval in June 2006; of those, 10.5 million doses have been distributed in the United States.3
Genital HPV infection can cause genital warts, usually associated with HPV types 6 or 11. The HPV candidate Cervarix (GlaxoSmithKline USA, Philadelphia) is formulated to prevent infection from HPV types 16 and 18.
The company submitted its application for the vaccine in March 2007 to the Food and Drug Administration (FDA). The agency asked for additional information in December 2007.
The company expects to submit its response to the FDA's complete response letter regarding Cervarix in the second quarter of 2008 and will continue discussions with the agency regarding the application, says Liad Diamond, company spokeswoman.
How to treat?
Treatment of genital warts should be guided by the preference of the patient, the available resources, and the experience of the health care provider, according to the CDC.5
For patient-applied treatment of external genital warts, look at two options:
- Podofilox 0.5% solution or gel. Advise patients to apply podofilox solution with a cotton swab, or podofilox gel with a finger, to visible genital warts twice a day for three days, followed by four days of no therapy. This cycle may be repeated, as necessary, for up to four cycles. The total wart area treated should not exceed 10 cm2, and the total volume of podofilox should be limited to 0.5 mL per day, according to the CDC. If possible, clinicians should apply the initial treatment to demonstrate the proper application technique and identify which warts should be treated.
- Imiquimod 5% cream. Patients should apply imiquimod cream once daily at bedtime, three times a week for up to 16 weeks. The treatment area should be washed with soap and water six to 10 hours after the application.5
What are some provider-administered treatment options? Consider the following options:
- Cryotherapy with liquid nitrogen or CryoProbe. Repeat applications every one to two weeks.
- Podophyllin resin 10%-25% in a compound tincture of benzoin. Apply a small amount to each wart and allow it to air dry. The treatment can be repeated weekly, if necessary. To avoid the possibility of complications associated with systemic absorption and toxicity, limit application to < 0.5 mL podophyllin or an area of < 10 cm2 of warts per session, and be sure there are no open lesions or wounds in the area to which treatment is administered. Some specialists suggest that the preparation should be thoroughly washed off one to four hours after application to reduce local irritation.
- Trichloroacetic acid or bichloroacetic acid 80%-90%. Apply a small amount only to the warts and allow it to dry, at which time a white "frosting" will develop. If an excess amount of acid is applied, the treated area should be powdered with talc, sodium bicarbonate, or liquid soap preparations to remove unreacted acid. This treatment can be repeated weekly, if necessary.
- Surgical removal. Choose from tangential scissor excision, tangential shave excision, curettage, or electrosurgery.4
References
- Dinh T-H, Sternberg M, Dunne EF, et al. Genital warts among 18- to 59-year-olds in the United States, National Health and Nutrition Examination Survey, 1999-2004. Sex Transm Dis 2008; 35:357-360.
- Dempsey AF, Koutsky LA. National burden of genital warts: A first step in defining the problem. Sex Transm Dis 2008; 35:361-362.
- Thompson D. Dealing cervical cancer a knockout blow. US News & World Rep 2008. Accessed at health.usnews.com.
- Centers for Disease Control and Prevention, Workowski KA, Berman SM. Sexually transmitted diseases treatment guidelines, 2006. MMWR 2006; 55(RR-11):1-94.
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