Spermicides May Ease HPV Transmission
Animal Study Shows Ingredient in Spermicides May Boost Transmission of Human Papillomavirus
July 2, 2007 -- A common ingredient found in over-the-counter vaginal spermicides may ease the transmission of human papillomavirus or HPV infection, at least in animals, according to a new study.
HPV infection causes genital warts and the majority of cervical cancers.
"Spermicides containing nonoxynol-9 may enhance the ability of the HPV to take hold in the genital tract, at least in animals," says researcher Jeff Roberts, MD, a postdoctoral fellow at the National Cancer Institute at the National Institutes of Health in Bethesda, Md. The study appears in the July issue of Nature Medicine.
While emphasizing that the study results are preliminary and may not hold true in people, Roberts tells WebMD that the findings deserve more study. Nonoxynol-9 is found in lubricants, contraceptive jellies and creams, and other birth control products. In recent years, its use has been found in some studies to boost the risk of transmission of HIV, the virus that causes AIDS.
The nonoxynol-9 and HPV link "will be news to most physicians," says Diane M. Harper, MD, MPH, director of the Gynecologic Cancer Prevention Research Group at the Norris Cotton Cancer Center of Dartmouth Medical School in Hanover, N.H. Harper, a leading expert on HPV infection, was not involved in the study but is familiar with the findings.
The researchers also found that using a vaginal lubricant containing the ingredient carrageenan seems to protect against getting HPV infection, even in the presence of nonoxynol-9.
Nonoxynol-9 and HPV
Roberts and his colleagues first pretreated one group of mice with the spermicide and another group with an inert substance, then exposed both groups to the HPV 16 virus, one of the "high-risk" HPV viruses thought to cause cervical cancer. A third group, not exposed to the virus or the other substances, served as a comparison group.
"One hundred percent of those exposed to nonoxynol-9 got infected" with HPV, Roberts tells WebMD. But the mice exposed to the inert substance were not infected.
Exactly why the spermicide seems to boost HPV infection risk isn't known, he tells WebMD.
WebMD attempted to contact several makers of nonoxynol-9, but none responded in time for publication.