The most common STI in the world - Emma Bryce

At some point, most sexually active people will be infected with human papillomavirus, or ‘HPV.’ There are over 100 types of HPV, and most of the time the body eliminates infections without symptoms—but some strains can pose serious health risks down the line.

HPV causes contact infections, which means the virus stays in the cells near the point of infection rather than spreading throughout the whole body. Since HPV is often transmitted through sexual activity, this usually affects the cells of the vagina, vulva, penis, anus, mouth, and throat. We can test for HPV in cells from these areas, but while testing for the virus is scientifically possible, it isn’t common. The main reason is that, while there are treatments for the adverse health effects caused by HPV, there’s no treatment for the virus itself. So testing for HPV would yield many, many positives, and although most of them won’t be cause for concern, there is still no treatment plan for clearing the body of the virus. But there are other good ways to protect yourself from HPV. We’re going to walk through how HPV can cause harm, who’s at risk, and how to minimize those risks.

The body’s immune system is able to eradicate most strains of HPV before they cause any harm—and without people even knowing they’ve been infected. Certain other strains—like HPV 6 and 11—cause abnormalities in the cells of the infected tissue, which can develop into genital warts. While these are infectious and require treatment, usually with topical creams, wart-causing strains don’t create longer-term damage. But another 13 strains can cause DNA mutations that cause cells to divide at a much faster pace than normal, propelling the development of cancerous growths. The cells of the cervix are especially at risk. Two in particular—HPV 16 and 18—are responsible for the majority of cases of cervical cancer, which is now the fourth most common type of cancer in women. It can take up to 20 years for cancer symptoms to appear, but with regular screening, we can discover cellular abnormalities in the cervix before they develop into cancer.

Women over 21 can undergo a regular pap smear, where a sample of tissue is gently scraped from the lining of the cervix to test for abnormal cells. A positive test doesn’t mean the person has cervical cancer, but rather that there are irregular cells in the cervix that could develop into cancer in the future. Patients are then either monitored with more frequent pap smears, or, for more severe irregularities, undergo a procedure called a colposcopy. This involves a doctor examining the cervix through a microscope, and possibly taking a small biopsy of tissue for closer examination. In some cases, the affected tissue may be removed.

HPV infections of the throat may lead to head and neck cancers, but for now there’s no equivalent of the pap smear for the throat. Using condoms helps prevent the spread of HPV during sex. And there are three safe, effective vaccines that all target HPV 16 and 18. The vaccine comes in two or three doses a few months apart, and it’s only beneficial if you receive them all. Right now the vaccine is part of standard care for girls aged 11 to 18 in many countries—though it’s increasingly becoming available to boys as well. Adult women and men in countries including the United States and the United Kingdom can opt to receive the vaccine, and evidence suggests that vaccination of women and men could reduce the worldwide incidence of cervical cancer by almost 90%. Researchers are also developing an injection for people who are already infected with HPV 16 and 18, which would target the infected cells to stop them from developing into cancerous ones.

So while there’s still room for improvement in screening, treatment, and access to each, condom use, vaccination, and cervical screening can each reduce the harm caused by HPV.