Colin Furness Profile picture
Canadian infection control epidemiologist. Student of knowledge management. Assistant Professor (teaching stream) Faculty of Information, University of Toronto
5 May
What went wrong with NACI? I have a theory, hear me out:

NACI confused relative risk with absolute risk, a rookie mistake, IMHO.

Side effect risk is higher for AZ than Pfz. That's what NACI was saying, and they're technically right about that.

BUT! ... 1/~6
If the risk of a serious side effect is .001% for AZ (1 in 100,000) and say, 0.0002% (1 in 500,000) Pfz, we could say that the relative risk is FIVE TIMES as high for AZ, and therefore Pfz is preferred. That's what NACI said, more or less.

BUT! ... 2/~6
But that's not a competent interpretation. A competent interpretation is that risk is very low for BOTH, and EITHER is much much less risky than contracting COVID, which is easy to demonstrate.

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