Researchers gave 12 women two vibrators each and detected the virus immediately after self-use on at least one of the vibrators used by all nine participants who tested positive for HPV.
Lead author Dr. Teresa Anderson, from the Indiana University School of Medicine in Indianapolis, said the small study is the first to examine whether vibrators could be transmitting the virus between sex partners.
"Sex toys used between partners within the same sexual encounter have the potential for transmitting HPV," Anderson told Reuters Health. "Cleaning the sex toy has the potential to decrease the amount of HPV DNA we can detect and so can potentially decrease the risk of transmission."
Genital HPV is the most common sexually transmitted infection in the United States. It is so pervasive that it has been called the common cold of the sexually active world.
HPV can be innocuous, but sometimes leads to warts and sometimes to cancer. The U.S. Centers for Disease Control and Prevention (CDC) estimates the virus causes an estimated 27,000 cervical, vulvar, vaginal, anal, penile, head and neck cancers among Americans each year.
The CDC recommends girls get one of two series of vaccines to protect against the type of HPV that causes most cervical cancers. Despite a push to immunize, less than 54 percent of U.S. girls between 13 and 17 years old were vaccinated in 2012.
The CDC also recommends that boys get one of the vaccines.
Current study participants were women between the ages of 18 and 29 who had engaged in sexual relations with both a man and a woman during the prior year. Anderson said she did not know if the participants had been vaccinated against HPV.
The investigators gave each woman a cleaning product, one vibrator made of thermoplastic elastomer - known as a "Rabbit"-style vibrator - and another made of soft silicone. They asked participants to swab the vibrators after vaginal use, immediately after cleaning and 24 hours later.
Nine of the participants tested positive for HPV, and the virus was detected on at least one of the two vibrators given to each of them. Just after use, HPV was found on all but one of the thermoplastic vibrators and on six of the nine silicone vibrators.
Even after cleaning, the researchers detected DNA from HPV on five of the thermoplastic vibrators and four of the silicone ones.
The silicone vibrators responded better to the cleaning after 24 hours. The researchers did not detect the virus on any of the silicone vibrators a day after cleaning, but they did find HPV on two of the thermoplastic sex toys.
The difference could be related to the porosity of the material, Anderson said.
She noted that the presence of HPV DNA does not necessarily indicate the presence of an infection. Additional studies would be necessary to determine whether an infection could be transmitted through sex toys, she said.
Cleaning vibrators may reduce the frequency of HPV transmission, the authors write. They call for more research on sex-toy materials, design and cleaning methods to most effectively reduce the virus' spread.
Once hidden in X-rated novelty shops, sex toys now line the shelves of major stores. Women also buy the devices at parties formerly reserved for kitchen products.
"I agree with the author that we need to study and identify safe and effective ways to clean sex toys," Dr. Jeffrey Klausner told Reuters Health. He is an infectious disease specialist at the University of California, Los Angeles and was not involved in the current study.
"When people are intimate, they're going to share viruses and germs. The good thing is that HPV is vaccine-preventable. The bad thing is the vaccination rates are very low," Klausner said.
"It probably would make sense for people not to share their sex toys," he said. But he added, "I'm not sure how practical it is during sex to start washing your toys."
Dr. Vitaly Smelov, from the Karolinska Institute in Stockholm, Sweden, told Reuters Health in an email that doctors should advise patients to clean their sex toys, particularly those shared between both same-sex and heterosexual partners.
In prior studies, more than half of women between 18 and 60 years old reported using a vibrator, and more than 65 percent of bisexual women reported partnered sex toy use, the current study's authors write in Sexually Transmitted Infections.
The medical community once thought that women who have sex with women were at low risk for HPV. But studies have since shown HPV infections are common among these women.
Research also suggests some women who have sex with women, particularly adolescents and young women as well as women who have sex with both women and men, may be at increased risk for sexually transmitted infections.