Wednesday, October 21, 2009

HPV Vaccine for Boys? No (and Yes)

The news about HPV vaccine for boys lately has been mighty confusing.

An FDA panel approved the use of an HPV vaccine in boys to prevent genital warts in September with a 7-0-1 vote.

Then an article came out in early October, sponsored by the CDC and others, suggesting that vaccinating boys to prevent cervical cancer in girls would not be cost-effective (more on that later).

And then today, a CDC advisory panel chose not to recommend HPV vaccination in boys. Apparently, the CDC-funded study weighed heavily in the committee's deliberations.

The upshot is that a doctor can write a prescription for HPV vaccination for a boy, but because it is not recommended, very few doctors will bring it up as an option, and no health insurance plan will pay for it.

Benefits of Vaccinating Boys Against HPV
1) The vaccine prevents getting genital warts. Sure, genital warts are mostly a minor nuisance, but tell that to someone who's had a few hundred warts cauterized up in his butt. Ouch!

2) The vaccine probably prevents anal cancer. No study is ever likely to prove that the vaccine prevents anal cancer. It is too rare, and takes too long to develop. But it doesn't take a genius to figure out that if the vaccine prevents getting the HPV strains that cause anal cancer, it will prevent anal cancers. Interestingly, this benefit is often dismissed as not a real problem, because most anal cancers occur in gay men (and nobody's son will grow up gay?).

3) The vaccine probably prevents a bunch of other, though rare, cancers - penis cancer (yes, there is such a thing), and cancers of the head and neck, primarily. Admittedly these are pretty rare. But if they can be prevented, why not?

4) Vaccinating boys prevents cervical cancer. Huh? But only people with a cervix (born female) can get cervical cancer. OK, but how are they getting HPV? From "Immaculate Infection"? No, from men and boys (for the most part). So, vaccinating boys is crucial to having a successful strategy for reducing the prevalence of these HPV strains in the population, thereby reducing the chances that a woman or girl will get infected, either because she didn't get the vaccine, or because it didn't work.

Lousy Vaccine Policy
The problem with contemporary U.S. vaccine policy is two-fold. Vaccination policy is strictly limited to worrying about individual risks and benefits, and vaccination policy is couched in terms of cost-efficacy, a framework that doesn't make sense.

Individual Benefits Only
So first, the individualized approach to vaccination strategy assumes that nobody else benefits from you getting vaccinated. So, if there is not an immediate benefit to you, don't get vaccinated. Because the individual, albeit miniscule, risk to you outweighs any potential benefit to others. And since men can't get cervical cancer, it is irrelevant that men and boys can infect women and girls with the virus that does cause cervical cancer in them.
That's not how vaccination policy has always been done. Smallpox vaccines were given to lots of people who had a next to zero risk of getting it, because the risk to society of having smallpox come back was too high. Same with polio. Today's vaccines are a lot safer than those vaccines were. The shift came with the HBV vaccine, when individualized risk-assessment was used to guide vaccinations, a policy that largely failed for the first two decades, and thousands of Americans are paying the price with HBV infections they didn't need to get, because a safe and effective vaccine was bottled up in a bureacracy of risk-assessment.

Cost-Efficacy. You're Worth $50,000 a Year.
Second, cost-efficacy is the wrong framework for evaluating vaccination strategy. For one thing, it is fairly arbitrary to say that a year of healthy life is worth $50,000, but not $100,000. By that logic, it wouldn't make sense to treat many forms of cancer, or advanced HIV infection, etc. Because if your treatment costs more than $100,000 in a year (which is not hard to do if you get surgery, chemo and radiation therapies), it exceeds the 'value' of your life for that year.
But that's exactly the logic of the CDC-funded article I linked to above. At $50,000 per year of healthy life saved, vaccinating girls is worth it. But at a little bit higher than $90,000 per year of healthy life saved, vaccinating boys isn't.
The study was also funded by the American Cancer Society, which recommends cancer screening programs that cost many times higher than that, and some of which (mammograms in women under 50, PSA tests), may well cause more human health harm than good, so could not be considered cost-effective at $10 billion per year of healthy life.

More fundamentally, cost-efficacy ignores any societal benefits acheived through reducing the prevalence of HPV infections. There is no space in the calculation for the benefits to society from reducing one's exposure to HPV because fewer people in the population have it. By the logic of cost-efficacy, if the vaccination strategy were somewhat effective, and reduced the prevalence of HPV infections by half, then the cost of a year of healthy life saved would rise to $100,000, and this logic would dictate that we should stop vaccinating girls at that point if the vaccinations are successful.
If we had pursued that strategy with smallpox and polio, we would have vaccinated people when the prevalence was high, but as soon as it got down to an acceptable annual cost to just let people get sick, we would have stopped the vaccinations, and we would not have eradicated smallpox from the Earth, or polio from almost everywhere.

Gloomy Predictions for HIV Vaccination Strategy
All the signs point to these forms of illogic being applied to the HIV vaccine, when it becomes available. First, vaccinations will be targetted only to "high risk" individuals, meaning that doctors won't think to ask if you want it, insurers will not pay for it, and you'll be hard-pressed to find it in-stock anywhere, meaning that you'll need to visit your doctor to get the prescription, go to a pharmacy to pick it up, and make another trip to the doctor's office to have it administered. Second, the logic of cost-efficacy will almost certainly exclude recommending any HIV vaccine - which will be expensive, require multiple shots, and be only partially effective (maybe 1/4 to 1/2 of people would be protected).
Getting a vaccine that works, my friend, is the easy part of this battle.

So forget what's recommended. If you can afford to get your boys vaccinated for HPV, please do it. For them, and for the girls.


  1. Cancer itself is a dangerous disease. Anal cancer is found in rare case. It affects to both male and female. Those who are consented to anal intercourse and with with depleted immune systems are more prone to this cancer. One should avoid smoking. If anyone observes symptoms of it, should consult doctor immediately.

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