A new study reported in the June 22 edition of the New England Journal of Medicine (NEJM) indicates that condoms are an effective method of reducing the risk of male-to-female transmission of human papillomavirus (HPV), a common sexually transmitted infection and a leading cause of cervical cancer. The study, conducted by researchers at the University of Washington in Seattle, refutes the results of earlier analyses – and a lot of healthcare information – concluding that condom use does not reduce the risk of HPV infection.

Most of the HPV prevention studies to date have been “cross-sectional” studies – studies that looked at volunteers’ condom use and HPV infection status at a single point in time. The University of Washington study is the first HPV prevention study to be “longitudinal,” enrolling women with similar characteristics and monitoring their HPV status and partners’ condom use over time. This, the researchers wrote in their NEJM paper, provides a more accurate way to evaluate the relationship between condom use and HPV transmission.

The study enrolled female undergraduates attending the University of Washington, all of whom were between the ages of 18 and 22. To qualify for the study, the women were required either to be virgins (never had vaginal intercourse), or to have had their first vaginal intercourse experience with one male partner within the previous three months.

Invitation letters were mailed to 24,201 female students. Of the 243 eligible women who responded, 210 agreed to participate. The women were followed in the study for an average of 34 months and visited the study site approximately nine times for HPV testing and Pap smears (to look for cervical lesions caused by HPV). The women also kept electronic diaries to record condom use after each incidence of vaginal intercourse.

Women whose partners used condoms for all instances of vaginal intercourse were 70% less likely to acquire HPV than were women whose partners used condoms less than 5% of the time. Even women whose partners used condoms more than half the time had a 50% risk reduction, as compared with those whose partners used condoms less than 5% of the time.

The study also found that women whose partners used condoms for all instances of vaginal intercourse were less likely to become infected with HPV strains known to cause high-grade precancerous lesions and cervical cancer: HPV types 6, 11, 16, and 18. What’s more, none of the women who reported consistent condom use had evidence of precancerous or cancerous cervical lesions, compared to some reports of precancerous lesions found in women never or inconsistently used condoms for vaginal intercourse.

While this study did not look at the effectiveness of condoms for the prevention of anal HPV infection, which can lead to precancerous and cancerous lesions of the anus, the reduced risk of HPV infection via vaginal intercourse when condoms are used correctly and consistently suggests a similar benefit for men and women who engage in anal intercourse.

These data also have implications for HIV-positive people. Cervical and anal HPV infection is common in people living with HIV and is associated with a high incidence of cervical and anal disease requiring diagnosis and treatment.

The results of this study along with others concluding that condoms are effective in reducing the transmission risk of HIV, gonorrhea, chlamydia, and herpes have significant public health implications. As written by Drs. Markus Steiner and Willard Cates, in an editorial accompanying the University of Washington report in NEJM: “First, persons who abstain from sexual intercourse or who are uninfected and mutually monogamous eliminate the risk of sexually transmitted infections. Second, persons who choose to be sexually active can be reassured that condom use can reduce the risk of most STDs. Third, like any other prevention tool, condoms work only when they are used. Consistent and correct use is essential for optimal risk reduction.”

Sources:

Winer RL, Hughes JP, Feng Q, et al. Condom use and the risk of genital human papillomavirus infection in young women. N Engl J Med 354:2645-54, 2006.

Steiner MJ, Cates Jr. W. Condoms and Sexually-transmitted infections. N Engl J Med 354:2642-3, 2006.