3 ms·
The annual flu shot is a guess. Due to manufacturing lead time and distribution the prediction for which strain will be the dominant strain in the future is mad
by chiefalchemist 4y ago
The annual flu shot is a guess. Due to manufacturing lead time and distribution the prediction for which strain will be the dominant strain in the future is made (afaik) approx a year earlier.
The point being, its possible any give year's jab is not the ideal jab given the strain that ended up the actual dominant.
Point being, the study should account for that, or at least explain the significance (or insignificance) of the match / mismatch. That is, is the jab creating an immune response that mitigates stroke. Or is the jab creating an immune response that mitigates flu and less flu means less stroke.
Otherwise, this feels like correlation.
- dashmeet 4y agoAnother variable that causes issues in the results is the effectiveness of the vaccine and the evolution of the virus over years with retained immunity. For example: A flu shot from years ago can protect against a flu from this year or in the future. So even if the flu vaccine isn’t effective in its current year, the immunity lasts for many years to those antigens. The strain of flu that’s currently dominant can fluctuate to newer or older variants. Controlling for this is even more confusing A guess this year could help in future years
- chiefalchemist 4y agoMaybe. Reference link(s), please.