Elusive HPV

The fight against human papillomavirus (HPV) has recently tallied some major victories. Research and immunization are reducing the number of HPV-related illnesses, including cervical cancer, which is almost always caused by the virus.

Though vigorous screening and Pap test campaigns (recommended up to age 65) have given the U.S. the lowest rate of cervical cancer on the globe, the cancer still affects some 10,000 American women annually. And the worldwide annual death rate from the disease is about 250,000.

HPV is an incredibly pervasive and varied virus—there are more than 100 known types. The chance that a woman will acquire HPV from her first sexual partner is nearly 30 percent after 12 months; the likelihood of a sexually active woman contracting it during her lifetime is perhaps as high as 80 percent.

But for a large percentage of infected women, there will never be any related illness, and the HPV may vanish—or become undetectable. "Ninety percent of HPVs just go away," says Patti Gravitt, PhD, an assistant professor of Epidemiology. Yet HPV can't be ignored, she notes, because certain types are known to cause cervical cancer.

To better understand HPV's seeming elusiveness, Gravitt is looking at its prevalence in women who are nearing menopause. In some cases, the virus is present in these perimenopausal women at rates nearly as high as young women who are becoming sexually active. Why the spike?

In a 2006 pilot study, Gravitt and colleagues found that single women, particularly those who were more sexually active, were more likely to have HPV. No big surprise. What did give them pause was that women who reported irregular menstrual cycles (those in perimenopause) or women using hormone replacement therapy were also more likely to have HPV.

"It was pretty striking," says Gravitt. "We found HPV in 21 percent of women who reported no recent sexual activity.

"Because HPV detection was more common in the women with evidence of hormonal changes," she says, "we wonder whether this is really new HPV or just a re-emergence of latent HPV the women acquired earlier in life."

Gravitt now aims to build on those findings with a full-scale study known as HIP (HPV in Perimenopause). "Our intention is to enroll 1,500 women, from ages 35 to 60," says Gravitt. "What does it mean to be HPV positive? The frank reality is that we don't know," Gravitt says. "HPV testing is being recommended as part of routine cervical cancer screening among these older women, and we'd like to be able to answer the inevitable question of, 'Where did I get this?'"