HPV Is Contagious for a "Complicated" Length of Time, Say Medical Experts

"The bottom line should be one of reassurance."

Human papillomavirus, better known as HPV, is one of the most common sexually transmitted infections around. According to the CDC, roughly one in four Americans is infected with the virus, which manifests as warts in some cases, as certain types of cancer in others, and occasionally doesn’t show up at all. Tricky as it is to avoid, it’s not always easy to tell if you or another person with HPV is still contagious. As researchers and sexual health experts tell Inverse, the short answer is: It’s complicated.

But fortunately, there’s a lot experts already do know.

How Common Is HPV?

First of all, H. Hunter Handsfield, Ph.D., professor emeritus of medicine at the University of Washington, wants people to know that getting one of the 200 different strains of HPV is basically a statistical certainty.

“Any story about HPV should say that people shouldn’t freak out about it. Everybody is going to get HPV, you can’t avoid it,” the former board member of the American Sexual Health Association tells Inverse. “It’s not something that people should go overturn apple carts in fear of getting.”

The majority of HPV infections only cause hand warts or are completely asymptomatic; that is, they don’t show themselves in any way and don’t lead to long-lasting health problems. But infection with certain strains of the virus do cause concerns.

CDC
More than one in four people will get HPV at some point during their lifetime, according to the CDC

In terms of genital warts, experts point to HPV-6 and HPV-11 as the primary suspects, though HPV-42, HPV-43, and HPV-44 can also cause genital warts, though it happens less often.

Twelve other “high-risk” members of the HPV family are associated with cancer in some patients, but the primary drivers are HPV-16 and HPV-18, which are responsible for roughly 70 percent of cervical cancers.

It’s these strains of HPV that are most important to understand in terms of activity and contagiousness.

How Long Is HPV Contagious?

As with many viruses, what makes HPV tricky is that just because an infection appears “resolved” doesn’t necessarily mean the virus isn’t still hiding out in cells in a latent state. Most HPV infections do clear up entirely on their own or with treatment, says Handsfield; in fact, 90 percent of infections clear after two years as the immune system learns to fight the virus, the World Health Organization reports.

“If you had genital warts and they’ve cleared up even on their own or with treatment and another three to six months go by, probably, for the most part, you’re not going to transmit them,” says Handfield.

“But the problem is that some HPV infections can be carried. That is, genetic material persists in previously infected tissues for a long time.”

HPV virus
An illustration of the HPV Virus 

Why Are Some Infections Recurrent?

In some individuals HPV infections are recurrent, which means that they tend to return, sometimes after years. Recurrent infections indicate that the virus is still present in the cell, oscillating between active and latent states.

Handsfield says it’s crucial to note that re-activation of the virus, which leads to the re-emergence of symptoms, doesn’t occur in most people. However, there’s seemingly no matter that determines who might end up with a persistent, recurring infection and who might avoid it if the person is otherwise healthy. A positive HPV test doesn’t distinguish between a newly acquired infection and one that was already there but has only recently reactivated.

Because of this, there is no simple answer long HPV is contagious. The bright side is that it busts a common myth about HPV infection: If one partner has HPV and the other doesn’t, it’s not necessarily a “sign of infidelity.” It could be a sign of a long-latent virus that had only recently become reactivated.

Can You Tell When The Virus Is Active?

Because the virus sometimes lingers but is not always active, there are many people who are unaware they are infected. June Gupta, MSN, the associate director of medical practices at Planned Parenthood, tells Inverse it’s essentially impossible to tell exactly when the virus is contagious and when it’s not. The absence of warts on its own isn’t enough to suggest that the virus is indeed latent.

“We actually have a very limited understanding at what points you might be contagious versus not. It’s not actually possible for an individual person to identify when it’s not dormant and can be passed,” says Gupta.

“At the end of the day, when I’m sitting with by patients, we really focus on the methods of prevention. That includes vaccination or condoms and dental dams and getting regular screening,” Gupta says.

How Can I Protect Myself and Others From Infection?

Because of this, the field is mostly focused on developing ways to prevent HPV emphasizing ways to prevent the “high-risk” HPV strains from progressing to more serious concerns, like cervical or anal cancer.

The HPV vaccine can prevent the majority of HPV types that are associated with cancer or warts. “It is biologically the most effective vaccine ever developed for any medical condition,” says Handsfield.

Still, the vaccine won’t clear out a pre-existing condition. Some studies, however, indicate that it might reduce rates of recurrent HPV infection. And pre-clinical research is investigating the effectiveness of certain cancer drugs on clearing HPV — specifically, hampering the virus’ ability to replicate.

This research is still in its infancy, but screenings and regular pap smears can detect the presence of an active virus, especially if its one of the strains that might be worrisome. These screenings can catch them before they become dangerous in terms of cancer risk. While researchers investigate new modes of HPV treatment, Handsfield, who has been studying the virus for decades, adds that it’s really nothing to be panicked about if the proper precautions are taken.

“The bottom line should always be one of reassurance,” says Handsfield.

Media via CDC (1, 2)