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Seasonal Flu Shots Double Risk of Getting Swine Flu, Says New Study
krou writes "A Canadian study currently under peer review apparently suggests that individuals given seasonal flu shots are twice as likely to get swine flu. The 'perplexing' study has thrown influenza health plans into disarray, with Quebec, Alberta, Saskatchewan, Ontario and Nova Scotia all suspending seasonal flu shots for anyone under 65 years of age. The study appears to be confined to Canada; the US, Britain, and Australia have not reported the same problem, so some are suggesting that the research has 'study bias.' However, the research appears to be 'solid' according to Dr. Ethan Rubinstein, head of adult infectious diseases at the University of Manitoba. 'There are a large number of authors, all of them excellent and credible researchers. And the sample size is very large — 12 or 13 million people taken from the central reporting systems in three provinces.''
I can see several reasons that those who obtain flu vaccines are more likely to contract the swine flu (as well as all the other versions of the flu.) First there's the age issue. The elderly are more likely to obtain a flu vaccine and are a higher risk group to begin with. But you also have the problems of people choosing to obtain the vaccine or not. Those who have never had a problem with the flu aren't likely to vaccinate themselves while those who have are more likely to obtain the vaccination. So in general you would expect those who obtain the vaccine to have more problems with the flu than those who don't.
That said, it's entirely possible the study accounted for all that, but we have no way to know as the study hasn't been published yet . It's only been distributed for peer review at this point.Until the actual methods are available, I consider this just another example of media sensationalism regarding the swine flu.
This is most likely a case of media hype driving public policy.
I heard a segment on NPR on this. Basically, it's just one study still in the very preliminary stages as studies go. Moreover, thee experts they interviewed said that there was no known biological reason why this would happen.
Given the amount of research into influenza, how to vaccinate against it, and how the bodies immune system responds to these vaccines, I think it's pretty safe to say that there won't be any medical surprises regarding the interaction between two such vaccines.
Until this is vigorously peer reviewed and at least another supporting study by other researchers is done, I call this a definite correlation (which we ALL know does not equal causation....right?).
Please consider the following from the article and the paper:
1) The vast majority of provinces have suspended vaccinations for people not over 65. These provinces likely have several individuals on their health boards with more qualifications than the average SD poster.
2) The sample size was 12 to 13 million people. The paper was written by a large group of very high level names, and the initial peer review results don't involve "sampling bias" or "conditional probability" attacks.
3) The vaccination DOES NOT boost the chances of normal flu, but DOES boosts the chances of swine flu. Accounting for age group and health differences, the trend still remains. People who have gotten vaccinated up to two years ago still show a statistically significant difference in their chance of catching swine flu.
4) Before the bandwagon leaves on the "people who are more likely to get sick are more likely to get vaccinated, accounting for the 100% increase", people who get vaccinations aren't twice as likely to catch flu as people who don't get vaccinations. There's definitely something going on here.
TLDR: This isn't some crackpot study or some anti-vaccination study. They noticed something weird, and like a good pack of scientists, are investigating it.
Signatures are the new names.
This might have something to do with it:
http://en.wikipedia.org/wiki/Original_antigenic_sin
The idea is that if your immune system learns to recognize an antigen similar to, but not sufficiently similar to, the antigen of a new threat, then your body may mount a less effective immune defense against the variant than it already knows. In other words, your body learns to fight seasonal strain of flu, then encounters similar H1N1. Now your body produces antibodies to the original flu, which bind more weakly to H1N1 proteins than an antibody that would have been made especially for H1N1, leading to an overall more severe infection than you otherwise would have had.
~Ben