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Does anyone know of a good resource that explains what 'efficacy' means for a vaccine, and what can (and cannot) be extrapolated from it? The reported efficacie
by roel_v 6y ago
Does anyone know of a good resource that explains what 'efficacy' means for a vaccine, and what can (and cannot) be extrapolated from it? The reported efficacies are (from what I understand) 1 - (n infections in experimental group / n infections in control group). But then I see people draw wildly varying conclusiona from that, most of which I suspect are wrong (e.g. the relationship between 'efficacy rate' and 'group immunity' after everyone is vaccinated). But despite looking long and hard, I can't anyone explaining in detail what such efficacy rates mean (and don't mean).
- tallanvor 6y agoI may screw this up, but efficacy describes how effective the vaccine was in the trial vs the control group. So if each group had an equal number of people, and 100 people in the control group got sick, but only 5 people who received the vaccine group got sick, the efficacy rate would be 95%. The hope, of course, is that the vaccine's effectiveness (how well it does at preventing covid) is close to the efficacy, but it's very hard to know for sure. That's why it's best to have the trials spread out among demographics and even locations, to better try and identify what may cause the vaccine to be more or less effective.
- radu_floricica 6y agoVery good point. I read recently that there were no hospitalizations in the AstraZeneca vaccinated group, so by this metric it's 100% efficient. I really want to hear those numbers as well, it makes a huge difference in the decision to promote a certain vaccine.
- gandalfgreybeer 6y agoI think this is a straightforward resource for explaining it. https://www.cdc.gov/csels/dsepd/ss1978/lesson3/section6.html https://www.cdc.gov/csels/dsepd/ss1978/lesson3/section6.html