Research Roundup: Not all "high risk" HPV is high risk, but some strains are really fucking scary: a one-stop shop for strain-specific studies available on the Web.

Most of the the time when you get a test for "high risk HPV," what you get is a grab-bag test that tells you you're positive for one or more of 13 or 14 types of HPV, but doesn't tell you which type or types you're positive for. This is kinda informative, but not really that informative, because cervical cancer risk varies a lot within the so-called high-risk types. 

How much does it vary? Some studies (summary and links below) show a 40% chance of having CIN3 within two years if you have HPV-16 and an ASCUS Pap. But with HPV-56 and an ASCUS Pap, the chance of developing CIN3 within 2 years is only 1.9%. Either HPV-16 or HPV-56 will give you a positive result on a "high risk HPV" test, but your level of risk is about 20 times higher if you have HPV-16. 

HPV types also vary quite a bit in median clearance time and in their potential to cause different kinds of cervical cancer. 

General practitioners and even gynecologists don't always know much about type-specific risk. (They've got other things to do, like seeing umpteen patients a day and fighting with insurance companies.) When I got HPV genotyping (which I didn't specifically ask for), I found myself in a bizarre situation where my doctor was telling me I had HPV-31, 56, 66, and 83, sounded kinda confused and worried on the phone, and couldn't answer key questions like "Are these strains really bad?" and "Is it bad that I have multiple strains?" 

This post should help answer the first question. The bottom line is HPV-16, 18, 31, 33, 35, 45, 52, and 58 are significantly more worrisome than the other "high risk" types, and you should be especially vigilant on your own behalf if you have HPV-16, 18, or 45, because they tend to cause disease of the glandular cells inside the cervical canal, which is harder to detect on a Pap.  

(The answer to the second question is "probably not"--there doesn't seem to be any link between clearance time or progression to cervical cancer and infection with multiple strains.)

Type-specific HPV geekery after the jump, and my apologies if this is too much of a data dump...

Hooey: "You can't get strain-specific testing for HPV." You can, and you might want to consider it.

When I first started looking into HPV, I read multiple places that genotyping or strain-specific testing was not commercially available. Then, when I asked my gynecologist to do an HPV test, the results came back listing four specific strains of HPV (31, 56, 66, and 83). Voila. I'd gotten genotyping without even asking for it.

So, "You can't get strain-specific testing for HPV" seems to be pretty much hooey. You can, you might get it even if you don't specifically ask for it, you probably can get it if you do ask, and there are some good reasons why you might want it. 

As usual, a bunch of geekery after the jump.

Hooey: "Older women are more at risk if they get HPV because their bodies have a harder time clearing HPV."

This is something you used to be told if you were over 30 or 35 and turned up with a new case of HPV. I strongly suspect it's something that women are still being told, because an over-35 friend of mine who had a positive HR-HPV test and an ASCUS Pap in 2007 was told this at a well-regarded women's clinic in our city. (And! Update! It's also something I was told at a well-regarded women's clinic in our city in 2012.)

It it true? Short answer: No, it's pretty much hooey, these studies found it was hooey, and a lot of the research showing it was hooey had been published by the early 2000s. If you're being told this today, your doctor needs to go do some reading and stop scaring old chicks for no good reason.

How about the long answer?

OK, first, some vocabulary, a few basics about HPV natural history, and a reminder about the differences between Pap testing and testing for HPV.

Hooey: "HPV Vaccines don't work if you've already been exposed to HPV."

If you rely on news sources and health websites for your information, you've probably heard that the HPV vaccination is "less effective after a person is sexually active," or "does not work for women already exposed to HPV."

Is this true? Short Answer: No, it's pretty much hooey. Is it important for young women to consider vaccination before they become sexually active? Yes. Does this mean the vaccines don't work for older women or women who have been exposed to HPV in the past? No.

While neither Gardasil nor Cervarix will help clear a current active HPV infection, both Cervarix and Gardasil are effective at preventing future HPV-16 and -18 infections in women previously exposed to HPV-16 and -18, and previously exposed women have a strong immune response to the vaccines. Gardasil reduced the incidence of persistent future HPV infections by 86.1% in previously-exposed women over 35, and Cervarix reduced those infections by 95.8% in women of all ages.

So, even if you are older, have a lengthy sexual history, or have had HPV-related cervical abnormalities before, you may want to consider HPV vaccination if you are currently testing negative for HPV-16 or -18 and anticipate new sexual partners. In fact, this may be even more true if you're over 35, because natural immunity to HPV wanes over time.

How about the long answer?

As usual, after the jump.

Personal Anecdote: Practically speaking, Cervarix is no longer on the market.

This is really more GlaxoSmithKline sales rep bait than a normal post, but truly:

Is Cervarix, Glaxo's HPV 16/18 vaccine with cross-protection for HPV 31 (and 45 and 33), still on the market?

From the patient perspective, it would seem the answer is "No."

I am in my 40s. Cervarix seems to induce stronger immunity in older women than Gardasil does. I am not positive for either HPV 16 or HPV 18, the two strains Cervarix primarily covers. I also don't have HPV 33 or 45, two fairly dangerous strains for which Cervarix, according to various studies, offers much better cross-protection than Gardasil. I would prefer to get Cervarix rather than Gardasil.

Yay Glaxo! I'm a sale, right?

Wrong.

I live in a large US city, with major hospitals, a research university, cancer research institutes, the works. I asked my doctor for Cervarix. He was willing to administer it off-label even though I'm over 25, but then...

No one can get me the vaccine.