The human papillomavirus has the dubious distinction of being the sexually transmitted disease you are most likely to get. It’s also the leading cause of cervical cancer. January has, somewhat arbitrarily, been dubbed Cervical Health Awareness Month (also National Hobby Month and Hot Tea Month, the last at least for good reason). While cervical cancer is the disease most commonly associated with HPV, a recent report from the American Cancer Society emphasizes that HPV’s threat is not gender-specific or organ-specific. While cervical cancer cases are in decline (as are general cancer rates), cancers linked to HPV are on the rise.

The increasing prevalence of HPV-linked cancers should permanently alter our limited conception of the disease as chiefly a women’s issue. Oropharyngeal (which I’ll be vulgarizing as “oral”) and anal HPV-related cancers (which particularly afflict men who have sex with men) are becoming more common. Oral malignancies account for 37.3 percent of HPV-related cancers, edging out cervical cancer, which makes up 32.7 percent. For men, oral cancers make up 78.2 percent of total HPV-related cancer incidences, and they account for 11.6 percent of cases among women. The death rate for oral cancer is three times higher than that for cervical cancer. (About 40 percent of penile cancer cases are HPV-related, but rates of the disease have basically remained static.)

Historically, most oral cancer cases were caused by smoking and heavy drinking and tended to manifest later in life. But even though fewer Americans indulge in these vices today, more of them are engaging in oral sex. Oral cancer rates have risen and begun showing up in younger individuals who, sensibly, seem to prefer oral sex to cigarettes. As the Oral Cancer Foundation notes, HPV strain 16 “is conclusively implicated in the increasing incidence of young non-smoking oral cancer patients.” If the disease is detected, the survival rate for HPV-related oral cancer is higher than for the alcohol- and tobacco-correlated versions. But HPV-related cases are often harder to catch because the disease occurs deeper in the mouth (the base of the tongue is a common location), and the warning signs are not as obvious.

There are, of course, HPV vaccines, which the CDC describes as “very effective” and “very safe.” Merck released another study in October that found that Gardasil, the company’s vaccine, may cause fainting and brief skin irritation but “no link with more serious health problems was found.” The Gardasil vaccine defends against four HPV strains: 6 and 11, which cause 90 percent of genital warts; and 18 and 16, which are linked to cancer. It is FDA-approved and CDC-recommended for males and females. Cervarix defends against the same two cancer-causing strains and a few other lesser culprits. It is not licensed for men. Most insurance companies and public health programs will cover the cost of the HPV shots for those who fall between the FDA-licensed ages of 9 through 26 years old.

But while both vaccines successfully defend against various strains of HPV, only Gardasil has been specifically tested and proven to protect against vulvar, vaginal, and anal cancers as well as cervical cancer. The vaccines’ preventive abilities have not been proven for other cancers, which prevents the companies from advertising the vaccines’ usefulness against the most prevalent danger: HPV-related oral disease. As the CDC notes: “It is likely that this vaccine also protects men from other HPV-related cancers, like cancers of the penis and oropharynx (back of throat, including base of tongue and tonsils), but there are no vaccine studies that have evaluated these outcomes.” Last year the National Cancer Institute declined to fund proposed clinical trials on the efficacy of the vaccines for oral cancer, possibly due to budgetary constraints. (NCI officials were not able to respond before publication.)

“The very low rate at which boys are vaccinated is a result of the inability of the manufacturers and doctors to speak openly and with factual evidence about oral cancer in a context that parents will understand,” says Brian Hill, president of the Oral Cancer Foundation, who was present at the National Institute of Health meeting where the aid was requested. He says more data and publicity for the vaccines could improve the vaccination rate in boys, which in 2010 was only 1.4 percent. “Vaccination is not just about cervical cancers but cancers their sons will potentially get in the future.”

The dangers of HPV may sound pretty disturbing, particularly for those who might have shrugged off the virus’s threat because they believed it wouldn’t imperil them or their children. But there are a few important things to understand about HPV. First, we aren’t all doomed. A lot of scary statistics get batted around about HPV—6 million new infections a year! Half of sexually active people will get it in their lives!—but most of the 130-plus strains appear to do no damage, and most people’s immune systems recognize the handful of dangerous strains as something nasty that should be destroyed.

But an unlucky 1 percent of the population will not produce the antibodies necessary to defeat the invaders. And it is basically impossible to know whether you or one of your partners is part of that 1 percent. There isn’t a reliable blood test to tell whether your body is making antibodies against the virus and is thus protected naturally and you don’t need the vaccine.

The vaccines work best in those who have never had sex and therefore have never been exposed to any strain of the virus. That means the safety and efficacy of the vaccines are of limited comfort to those who were sexually active prior to 2006, when the vaccine first became available to females (in 2009 males were officially given the OK).

After a certain age, 26 in the United States, it is assumed most people have had enough sexual partners that they have been exposed to HPV and their bodies have produced the antibodies necessary to defeat it on their own. In the case of women who have been exposed and developed an infection, it is thought that cervical abnormalities will have been detected and dealt with. Vaccinating people after a long sexual history simply isn’t worth the cost, from a public health perspective.

But age isn’t always a reliable measure of sexual activity, particularly for those who, say, married young and are getting a divorce and re-entering the dating scene. “If you vaccinate a 45-year-old woman who hasn’t had a cervical HPV, the vaccine will work for her as well,” says Aimée R. Kreimer of the National Cancer Institute. One study shows the vaccines, which guard against multiple varieties of the virus, can be effective in older women who have not been previously exposed to all of the targeted strains. Another study even suggests that the vaccine prevents further HPV outbreaks among women who have already been treated for cervical infection. “Our findings clearly show that those who have the disease can be protected from new disease and dispels the myth that only young and virgin girls can benefit from the vaccine,” says Elmar A. Joura of the Medical University of Vienna and an author of a study published last year in the British Medical Journal. “The earlier you vaccinate the better, but the benefit never really stops. It prevents new infections for sure, independent of age.”

Unfortunately, the decision about whether to get vaccinated or not isn’t a simple one. Gardasil and Cervarix have no therapeutic properties, and once someone has caught one of the strains, the vaccine is no longer protective against that particular infection. There is no reliable blood test to show which HPV strains someone has been exposed to, so it is always possible that the vaccine could be beneficial—or not. But overall, the longer someone has been sexually active, the less likely the vaccine will be of use, which is why public health campaigns focus on the young.

Most nations with universal health care also have rigorous cost-control measures and do not cover the HPV vaccine for people in their 20s. The exact age varies: In the United Kingdom vaccinations are free for those 11 to 17 years old. In Canada, where vaccination programs are run by the provinces, free shots are chiefly available to school-aged women. The same is true in most European nations. Studies like Joura’s have inspired many countries to raise their age recommendations beyond America’s 9 to 26 years old—Canada suggests the vaccine for women up to the age of 45—but those who aren’t covered by the public vaccination programs have to pay for it themselves. “This [hypothetical older] woman is probably not cost-effective in a vaccination program, but when she is looking for the personal benefit she clearly gets it,” Joura says.

America’s patchwork of private and public providers are often more generous with free vaccinations than are health care systems in other developed nations. Many insurance companies will cover the cost of the shots for those up to the age of 26, as will many publicly funded programs for children, and in some states adults, without private insurance.

The FDA’s age-licensing limitations or the CDC’s age recommendations do not mean that it is a bad idea for those older than 26 to get the HPV vaccine. But the cost of the vaccine in most cases has to be paid out of pocket, to the tune of about $390 to $500. Is it worth it? That’s a personal judgment call. The fewer sexual partners you’ve had, the less likely it is that you’ve already been exposed to the HPV strains the vaccine defends against. If you anticipate having new partners (potentially with new virus strains you haven’t been exposed to before), you may well still benefit from the vaccine.

For people who haven’t encountered all of the HPV strains in the vaccine, says Alex Ferenczy of McGill University, “the efficacy of the vaccine is still outstanding for those remaining virus types to which they were not exposed before the vaccination.”

One more reason to consider the vaccine is that it is unclear whether antibodies, either induced by an actual HPV infection or the vaccine, have a half-life. That means protection may not last forever. This is true of other antibodies: The immunity conferred by a childhood brush with chickenpox may not last to protect us from shingles, which is caused by the same virus, later in life. It is known that vaccine-induced antibodies or those produced naturally in reaction to an HPV infection last 10 years. But they have not been proven to last a lifetime. If they don’t last, this is another possible reason why the vaccine could be effective in women in their 40s, but there is not enough research to prove or disprove this premise.

The vaccine is most useful for young people who are least likely to have been exposed. But by this measure, America is failing. Due to our long history of anti-vaccine hysteria, and some conservative politicians’ perennial efforts to politicize anything remotely related to sex, HPV vaccination rates in the United States are terribly low. Only 32 percent of girls ages 13 to 17 have received the full three-shot regimen, which is significantly less than in Canada, Great Britain, and some regions of Mexico (although much of the European Union has similarly dismal rates). Like most health issues in the United States, HPV’s worst consequences are unequally distributed, with cervical, anal, and penile cancer rates all higher among lower-income populations who tend to be poorly covered by insurance programs and have less access to health care.

For those who are under 26, getting vaccinated will likely be free. Since it is impossible to know how effective the vaccine may be in your case, it’s worth getting—it won’t hurt you or your wallet. For those over 26, vaccination can be an expensive decision, but it may well be worth it, particularly if you haven’t had many sexual partners or are expecting new ones. But to get the most bang for our public health buck, America needs to muster the political will to establish HPV vaccination programs for schoolchildren, both boys and girls. We already require vaccination of children against another sexually transmitted infection before they enter school: hepatitis B. HPV vaccination is an easy and safe way to spare kids a lot of pain and fear later in life.