Deadly dose? No. Here’s what we’re really wondering about the HPV vaccine.

virus
 Katie Couric spotlighted the HPV vaccine in a recent show, asking a very odd question: “The HPV vaccine is considered a life-saving cancer preventer, but is it a potentially deadly dose for girls?” It’s pretty clear that the answer is no. Matthew Herper at Forbes has a great explanation of why Couric’s story is a skewed telling of what we really know about the vaccine.

Now, I’m not a Katie hater. I love that on her website, the headline “What You Need to Know About the HPV Vaccine” leads to a doctor’s explanation of why she recommends the vaccine for her patients, and why the stories of people who believe they were harmed by the vaccine—like, ahem, some of the guests on Couric’s show—don’t add up to a real safety concern.

If you’re swayed by the personal stories of women who claim their daughters were hurt by the vaccine, take a minute to look more closely at the cases. They typically involve an “unexplained death” or a disease that can develop spontaneously or with unknown causes. This is tough on anyone, and certainly the deaths and diseases are tragic. But that doesn’t mean they’re linked to the HPV vaccine. In dozens of these stories, the only connection to the shot is the patient or, more often, the parent deciding that there was no obvious cause, so by process of elimination, a shot received days, weeks, or months earlier was blamed. Even one researcher fell into this trap; primary ovarian failure, basically early menopause, has no discernable cause in many cases. She found three of those girls who had gotten the HPV vaccine, and declared the vaccine to be the cause. It’s a classic “after this, therefore because of this” observation: not a convincing argument on its own, but a hint that there may be safety concerns worth investigating.

And safety concerns have been investigated, most recently in a study of nearly a million girls in Sweden and Denmark. It was a beautiful opportunity to find dangerous effects of the vaccine, if there were any. And the researchers came up empty-handed. One of the researchers told Reuters, “There were not really any concerns before our study, and no new ones after.”

Another reason to applaud Couric: it’s great to ask and answer questions about the vaccine, especially a new and somewhat confusing one like HPV, in a public forum. In fact, there are some really important questions to ask about the HPV shot, but most of them weren’t highlighted on Couric’s show. Here’s what I really want to know:

1. How long does immunity last?

A researcher on the show, Diane Harper, claimed there was no evidence that the HPV vaccine is effective beyond 5 years. That’s worrying if true: a boy or girl who gets the shot at age 10 could be unprotected at age 15. In that case, the shot would have to be given every five years or so, and might lead parents to delay the shot (why not skip the 10-year shot, and start at 15?) if they are in denial about the possibility of their child becoming sexually active as a teen. As we’ve discussed here before, that happens, both with and without consent.

But there’s reason to doubt Harper’s claim of a 5-year limit. For example, these two studies found good protection after 8 years. The study is ongoing, so we’ll get updates in years to come.

2. Can it prevent throat cancer?

OK, first I have to correct something I said last time I wrote about HPV. It turns out that Michael Douglas did not have an HPV-caused throat cancer. That was a story released to the press, to cover for what he actually had: a very scary tongue cancer. In the end, Douglas got to keep his tongue and jaw, and revealed the truth.

But it’s true that HPV causes many head and neck cancers. Unfortunately, it’s hard to study prevention of oral HPV. The vaccine might prevent it, but there’s no oral counterpart to the HPV testing done in cervical screening, so no way to test whether a vaccine prevents oral cancer without a truly massive, long term study.

3. Why not give it to people older than 26?

The vaccine is only approved for the causes and populations it was tested on, which include women up to age 26. Another valid question would be: why not give it to 27-year-olds and up? Many adult women today never had a chance to get the vaccine as a teen, but are still being exposed to the virus and at risk for cancer. Currently, they’re being told their only defense against HPV is keeping up with cervical screening. Admittedly, this catches most HPV before it becomes cancer, but not everybody keeps up with screening.

4. Are we using the right strains?

HPV comes in many flavors, some harmless, some cancer-causing. Both the Gardasil and Cervarix vaccines include types 16 and 18, because they were thought to account for 70% of cervical cancers. But that number may reflect limited test populations. A recent study shows that types 16 and 18 are less common in African-American women than in white women. Both groups have similar screening rates, but African-Americans are more likely to die of cervical cancer. This adds up to a suspicion that there are other cancer-causing HPV types that tests aren’t looking for and vaccines aren’t preventing.

(Virus image from jiparis via Flickr.)

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The Deadly dose? No. Here’s what we’re really wondering about the HPV vaccine. by Public Health, unless otherwise expressly stated, is licensed under a Creative Commons Attribution 3.0 Unported License.

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4 Responses to Deadly dose? No. Here’s what we’re really wondering about the HPV vaccine.

  1. Pingback: RiskScience RISK BITES: Why vaccinate against HPV? - RiskScience

  2. Joanne A says:

    You wrote “The vaccine is only approved for the causes and populations it was tested on, which include women up to age 26″. But I thought the vaccine was approved, and indeed recommended for, boys of that age as well? So surely it was tested in boys?

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  3. Pingback: Impact of Katie Couric’s misinformation on HPV vaccine in one image | Dr. Jen Gunter

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