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The human papillomavirus (HPV) raises the chances someone will get head and neck cancer by at least sevenfold and maybe much more, researchers reported Thursday.

It’s been known that HPV can cause head and neck cancer, but this study shows just how much it affects the risk.

The good news is the virus can be prevented with a vaccine, and a mouthwash test can tell a doctor who’s most at risk.

Dr. Ilir Agalliu and colleagues at Albert Einstein College of Medicine in New York looked at the records of more than 96,000 people taking part in a big medical study.

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They all took a mouthwash test for oral HPV infection as part of the study. Four years later, 132 of them had developed some form of head and neck cancer. The researchers compared each patient with cancer to three similar people who didn’t get it.

People infected with a strain called HPV-16 were between two and 22 times as likely to be in the cancer group, the team reported in the Journal of the American Medical Association’s JAMA Oncology.

Experts believe 70 percent of all head and neck cancers are caused by HPV, likely spread by oral sex. According to experts, by 2020 head and neck cancer will beat out cervical cancer as the most common HPV-related cancer.

Before the 1990s it was thought that head and neck cancers were caused by smoking and drinking, but over the past 30 years there has been a sharp spike in these cancers in heterosexual males, leading experts to look for another explanation.

HPV, already known to cause most cases of cervical cancer, as well as cancers of the anus and penis, turned out to be the cause. It really hit the headlines 2013 when actor Michael Douglas announced that he was being treated for throat cancer and said he believed it was caused by HPV.

Two FDA approved vaccines — Cervarix and Gardasil — prevent infection with HPV strains 16 and 18. Gardasil additionally covers the wart-causing strains 6 and 11. A new form of Gardasil, approved earlier this year, adds five new high-risk HPV strains to its coverage, for even more cancer protection.

Both boys and girls are supposed to get three doses of the vaccine, starting at age 11 or 12.

There are 109 known different types of human papillomaviruses (HPV). They cause warts and other lesions, and two-thirds of Americans are infected.