Seasonal flu shot increases risk of H1N1 infection?

This idea has been knocking around for a a few days, and is regularly discussed by David Dobbs at his blog. This concerns me quite a bit, as my wife is 8 months pregnant, flu is a very serious risk for pregnant women and their babies, she teaches in a high school, and got her seasonal flu shot last week. It's called the Hoskins effect and it seems to happen now and then with viruses.

Here's the story: There is a study coming out of Canada, done in Canada, that seems to show that in Canada people who get the seasonal flu shot have an increased, perhaps doubled, chance of getting H1N1

The way this would work is like this: If your immune system gets trained to handle a certain infection, it focuses a bit too much on that specific version of the infection and ignores other similar infections. All the soldiers are at the wrong side of the castle, as it were.

There is a story in the Globe and Mail about this, Here is David Dobb's original post on this, and if ERV has not written about it yet, tell her to.

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I think this fuss is premature. The manuscript just went out for peer review, and I have yet to see evaluation from anyone who's actually seen the data.

I'm betting on a skewed population. People who are more vulnerable to infections (e.g. immune suppressed) are recommended to have the flu shot free of charge. Perhaps they are more likely to get H1N1 for the reason that they have the flu shot and/or under a physician's care so more likely to get tested?

It's science by press release, which I really, really. really hate, particularly since the antivaxers have been running with this. In any case, as has been pointed out, it hasn't been published in a peer-reviewed journal yet, and we have no way of evaluating the methodology or whether these researchers are full of crap. I'd wait for the study to be published before anything.

And, remember: Whenever scientists publish by press release, be very, very skeptical.

Actually, I meant to say "science by press leak," not press release. Which is even worse than science by press release.

This is definitely not science by press release, as you say, but rather, by leak. I'm not sure why leak is worse than release, I would have thought the opposite.

Given the rapidity with which situations like this develop, ten or twenty days starts to feel like a long time. They really should get this thing out so people can simply see it and do what they need to do to evaluate it. The anti-vaxers are always going to be a pain, I don't think that should drive any serious thinking on this other than to continue to explain to them why they are wrong.

Cheer up; at 8 months, the baby-to-be has all its large and small parts and is just fattening and maturing. In the first few months, while everything is still forming, a viral infection is much more dangerous.

You're probably not in a high-risk group anyway, so will probably get the second wave of shots (with the first tranche going to the elderly and front-line health-care workers), right? So by then you'll know more.

with the first tranche going to the elderly and front-line health-care workers

Being in a low-risk category, despite being a front line health care worker, I'll pass....
I read about this a while ago, and didnt think it made much immunological sense, but yeah, let's see what the studies show.

By Rorschach (not verified) on 05 Oct 2009 #permalink

Read the fine print: the "seasonal flu shot" that's a possible risk is last year's -- not terribly useful information for making decisions now.

By D. C. Sessions (not verified) on 05 Oct 2009 #permalink

DC: There is ambiguity about that. It is not clear if we are talking about a risk to those who happen to have last year's shot vs. those getting new shots this year. Also, if this is the Hoskins effect, that could be a matter of how novel H1N1 behaves, not how the shot behaves. But of course, this could well depend on the exact shot and other factors, which could in turn explain why the effect, if it even exists, may (or may not) exist only in Canada. If that turns out to be true.

Obviously, what is needed is for the paper to get out so we have a clue what is being talked about. That is the bottom line and everything else is speculation. The problem is, it is speculation about important stuff (potentially) and whether this conversation remains as speculation or developes to be something else is up to the publishers at this point.