Saturday, November 05, 2005

theCSO: More on the HPV vaccine..

There is another reason for this, one I see as primary. One of the major scare tactics used by the abstinence-only folks is "Condoms haven't been proven effective against HPV, so you could catch HPV even if you use a condom.. better wait until marriage."

They're mostly banking on how HPV has a very similar acronym to HIV. Nevermind that condoms, properly used, have been proven highly effective against HIV which, unlike HPV, is deadly. Nevermind that HPV has no serious symptoms (and is often completely asymptomatic) except for the cervical cancer risk, and that there IS evidence that condoms reduce that risk. For that matter, nevermind that the increased cervical cancer risk is actually quite small.

When it comes down to it, I think the real issue is that this vaccine would take away a favored arguement against premarital sex. I don't think it's the reason anyone will rally around, but I think it's a large part of the real issue.

I do wonder what the religious right would do if an effective HIV vaccine was to be announced. Would they oppose mandatory vaccination?

Also, there's a quite different question about this vaccine, one that probably won't be asked as much as it should be. And I'm not anti-vaccination in general. I have some reservations about the chicken pox vaccine for this same reason, but generally support vaccine and mandatory vaccine programs.

Basically, the only group that needs this vaccine from a *clinical* perspective is girls. And even then, the risk that's being protected against is pretty small. In men, HPV is generally asymptomatic and doesn't increase the risk of any disease, so there really isn't a clinical reason to inoculate boys. There isn't even a good *test* for HPV in men - in women, there's a limited test for some of the high-risk types that can be done during a pap smear. Even there, the treatment is basically "Be really sure to not skip your next pap smear, just in case." From a public-health perspective, it makes sense to eliminate a reservoir, so any mandatory vaccination program would have to include both.

There is also the consideration that it would reduce the number of 'nuisance' cases by preventing the three most common strains that increase cervical cancer risk - but that's only some of the high-risk types, and not even the low-risk types that cause more visible lesions. It's also possible that widespread vaccination against these more common strains would help make the other strains more common.

Basically, it comes down to whether preventing a few cases of cervical cancer and some people from getting annoying but treatable warts that eventually go away is worth the risk and expense that goes into vaccinating everybody. Chicken pox doesn't kill or cripple in kids either, it's just annoying, and the chicken pox vaccine got pushed through on that basis.

This is about money, just like the chicken pox vaccine was. Merck would love to sell millions of doses of this vaccine, and what better way to do that than to make it mandatory?


Kim said...

I've been hearing for thirty-five years that cervical cancer was from this virus.
Two questions: why are they just coming up with a vaccine now and not twenty years ago?
and Why isn't it contageous if it's a virus? I mean why isn't cancer contageous?

TheCSO said...

An excellent Planned Parenthood fact sheet on HPV

Basically, cancer isn't contagious because the viruses just increase cancer risk, they don't actually *cause* cancer. Some viruses can damage the safeguards cells have against becoming cancerous; the impact is much greater if there are other risk factors as well. For instance, smoking also increases cancer risk, so smoking + HPV-16 is a much higher (but still very low) risk of cervical cancer than HPV-16 alone.

HPV has been found to be a factor in most cases of cervical cancer, but most people with HPV, even the high-risk strains, don't get cancer. HPV infections are usually cleared by the body within a year even without any sort of treatment. That does make me wonder about why it's so urgent that this vaccine be administered to kids.. kids and young adults don't get cervical cancer often, while any HPV infection a young or even college-age adult would get will probably clear up on its own long before they're old enough for most cervical cancer to occur.

Also, let me address the "100% effective" claim Merck has been making. There's some fine print there that usually gets glossed over by the media. There was a trial where the vaccine was 100% effective at preventing infection by the most common high-risk strains (NOT all HPV, or all high-risk strains) for the period of the trial. That does NOT prove that the vaccine will still provide even that level of protection twenty or thirty years later, when cervical cancer becomes more of an issue.

I don't think we know enough yet to make a fully informed decision on this vaccine. And, unfortunately, we may not be able to get that information without a mass vaccination program.