Among virologists and infectious disease researchers, there have been longstanding debates as to common routes of transmission for the human papillomavirus (HPV). HPV infects the skin and genital area, in many cases leading to a variety of genital, anal, and oropharyngeal cancers in men and women. Strong evidence exists showing that penetrative genital sex and oral sex can transmit HPV. However, while HPV is also often detected in the hands, the question of whether hand-genital contacts can transmit HPV has come into question through a new study led by investigators at McGill University.
Finding from this new study were published recently in The Lancet through a study entitled “Hand-to-genital and genital-to-genital transmission of human papillomaviruses between male and female sexual partners (HITCH): a prospective cohort study.” The research team concluded that unlike being genital HPV positive, having HPV in your hand does not increase the risk of transmitting HPV to a sexual partner.
A centerpiece of the longstanding debate is the fact that HPV types in the hand generally match those in your own and your partner’s genitals. This has led some researchers to hypothesize that hand-genital sexual contacts could be enough to transmit HPV infections.
“Just because we detect HPV DNA in the hand doesn’t necessarily mean the viral particles are viable or that there is enough to cause an infection,” noted lead study investigator Talia Malagón, PhD, a postdoctoral researcher at McGill University. “The DNA might just have been deposited on the hand because a person recently had sex or touched their own genitals.”
While other studies have looked at HPV in sex partners’ hands before, the McGill study is the largest and the first to explicitly disentangle whether hand-to-genital HPV transmission can occur independently of genital-to-genital transmission. The results provide the strongest evidence to date that hand-to-genital HPV transmission is unlikely. “Indeed, we found that most HPV detected in the hand likely came from a person’s own genital HPV infection,” stated senior study investigator Eduardo Franco, DrPH, chair of the department of oncology at McGill.
Having seen data from another research group showing that sex partners tended to have the same HPV types in both their hands and genitals, the researchers realized they could easily examine this question in their own HITCH study, but with a much larger sample size.
“We found the same results as this previous study but decided to take it a step further by controlling for infections in both the hands and the genitals to disentangle which had come first and whether it was the hand or the genital infections that were responsible for HPV transmission between partners,” Malagón remarked.
The researchers added that that the results do not necessarily mean that it is impossible to transmit HPV from hand-genital sex. “It just means that if hand-to-genital HPV transmission does happen, we have not observed it, and it is therefore rare and unlikely to explain how most HPV gets transmitted,” Malagón stated.
“HPV is very common, and most sexually active adults will become infected with HPV at some point in their lives, without realizing it, before their immune system clears it,” Franco concluded. “Our study suggests you are much more likely to get and transmit HPV through penetrative genital contact than from performing hand-genital sex. Condoms can reduce your risk of infection, but they only provide partial protection. The most effective prevention against infection and the cancers HPV causes is therefore vaccination. Women can also get screened to prevent HPV infections from progressing to cervical cancer.”