SAN JOSE, Calif. -- Few people have heard of the human papillomavirus -- and even fewer know they have it -- yet the venereal disease now infects more than half of all women who have been sexually active for at least several years, according to a study published Wednesday.
Researchers, who followed hundreds of San Francisco Bay-area women over a 10-year period, think the virus, also known as HPV, could end up affecting more than two-thirds of all women during their lifetime. And, if they don't receive regular Pap smears, some could end up with cervical cancer as a result, they said.
"The risk of acquiring HPV is actually quite high. A woman's lifetime risk is around 70 percent," said Dr. Barbara Moscicki, a researcher at the University of California-San Francisco whose findings were published in the Journal of the American Medical Association.
The report comes from what is considered the longest-running study of the virus, involving more than 800 young women since 1990. The research supports many prior assumptions about HPV, primarily that the sexually transmitted disease is the leading factor in cervical cancer.
But the new data also indicate that for most women, HPV is not necessarily a lifelong infection, as was previously thought. Nor does it appear to lead to cancer in the majority of women who get it.
The study found, however, that the several dozen strains of viruses that make up the HPV family are very easy to catch. For every new sexual partner a woman took, her risk of being infected with the disease jumped tenfold.
HPV is now considered the most common sexually transmitted disease, and it isn't difficult to understand why: Condoms provide only minimal protection from the virus.
Yet public-health experts note that the majority of people exposed to the virus will never experience any negative effects from it. While several strains of HPV can result in genital warts, most cause no itching, no soreness, no vaginal discharge, no visible outbreaks and no pain. For men, the only known symptom is genital warts, which are relatively rare.
The study had some encouraging findings. While other scientists had theorized most women infected with one of the nastiest strains of HPV would be at risk for cervical cancer, Moscicki's team determined that is not the case. Less than one-third of women with HPV develop lesions that put them at risk for the disease. And about 90 percent of these women had strong enough immune systems that their lesions went away -- along with their chances of getting cervical cancer.