Beth wrote, “I plan on having my daughter vaccinated against HPV when she’s the right age (which is what by the way?). Recently, some friends were saying they were planning to have their sons receive the vaccine as well because although males obviously don’t get cervical cancer, they can spread HPV and put their future partners at risk. Is this true?”

Yes, men can catch HPV infections, and spread them to women. But that might not be reason enough to have your son vaccinated.

First, background: HPV (human papilloma virus) is by far the most common sexually-transmitted infection. About 50% of all men and women will be infected by at least one strain of HPV at least once in their lives; about 20 million Americans are infected (and infectious) right now, and 6 million new cases of HPV infection occur each year in the United States. There is a lot of virus going around.

HPV is the direct cause of genital warts. It also causes cervical cancer (12,000 new cases a year in the United States), vulvar and vaginal cancers (4,000 per year), as well as cancers of the anus, head, and neck in men and women. From a pediatric perspective, it can also cause warts in the airways of young babies exposed during childbirth, which can be lethal or very difficult to treat. However, most people infected with HPV do not develop any of these long term problems—the virus is cleared by the immune system.

Most cancers are caused by two specific strains of HPV, and those strains are included in both brands of HPV vaccine (Gardasil and Cervarix.) About 70-80% of cervical cancers could be prevented by widespread use of these vaccines. Gardasil also protects against  two other HPV strains that cause genital warts. Though Cervarix doesn’t include these two wart-causing types, there is some evidence for cross protection these and other strains from the vaccine.

Both HPV vaccines are very safe. Despite media scaremongering and a hysterical anti-vaccine movement eager to encourage the spread of disease, there have been very few serious reactions to these vaccines. The most common reaction is pain at the injection site (these vaccines do seem more painful than others). There have also been reports of fainting after HPV vaccine, which isn’t unexpected among teenagers after any injection or medical procedure.

So why wouldn’t you want to give these vaccines to boys?

1. The diseases they prevent in men are quite rare, far rarer than cervical cancer. For instance, penile cancer affects about 1,000 men each year, compared to 16,000 women who get cancer of their reproductive organs. Though HPV can contribute to cancers of the head and neck in both men and women, smoking accounts for far more cases of these diseases.
2. It’s difficult to prove that this vaccine actually works in men. The point of the vaccine is to 1. prevent HPV infection, which 2. prevents HPV from causing cancer. In women, early HPV infections can be demonstrated by pap smear—there is no similar way to show that men have caught HPV. Blood tests in both men and women can serve as “surrogate markers” of infection, but aren’t really accurate for specific patients to predict disease. Cancers develop rarely, even in infected people, and they may take years or decades to develop. Penis cancer is primarily a disease of elderly, uncircumcised men. Following boys for 50 years to see how many of them develop penis cancer is nearly impossible. So whether HPV vaccination prevents cancer in men will be difficult to prove. Not only that, but we can’t even be sure that vaccination prevents men from spreading HPV to their partners—again, it’s very difficult to know what men are even infected, so correlating new infections in their partners would be logistically impossible. That doesn’t mean that the vaccine doesn’t work, just that it’s hard to prove that it works to the same degree that we require proof of effectiveness of other vaccines.
3. It’s very, very expensive. A three-dose course of HPV vaccine costs me about $400, plus administration and storage and other associated costs. Is that worth it?

There are some high risks groups of boys who ought to be more-strongly considered for HPV vaccinations. Men who have sex with men are at especially high risk for HPV-associated cancers, probably about 17 times the population risk. And men with immune-compromising disorders, like HIV infections, are at a very high risk both for cancers from HPV infections, but also for extensive warts that are more-difficult to treat.

A legitimate question: how would most parents know that their son might be engaging, or might later engage, in higher-risk sexual activities? Since you might not know, perhaps it would be best to vaccinate all boys. I can see both sides of that argument.

At this point I would confidently say that all girls ought to be vaccinated—both the safety and effectiveness have been well demonstrated. The FDA has approved HPV vaccines from age 9-26, and the AAP recommends girls begin the three dose series at age 11 or 12. All three doses (which are typically given over six months) need to be received prior to the first sexual encounter to work best. In my clinic, most of my patients have stable homes with good health insurance, so I think it’s reasonable to begin vaccinations a few years older than the AAP recommends, but if you’re not sure you’ll still have health insurance next year, start the vaccines when they’re covered.

Currently, the AAP and CDC take a “permissive” stance on HPV vaccines for boys, and I agree with that. It’s a vaccine that parents ought to consider, but because of the shortcomings discussed here, it’s not “recommended” for all boys. It may also not be covered by health insurance, so you might want to ask about that and the retail charge before your son is vaccinated.

Roy Benaroch is a pediatrician who blogs at The Pediatric Insider. He is also the author of Solving Health and Behavioral Problems from Birth through Preschool: A Parent’s Guide and A Guide to Getting the Best Health Care for Your Child.