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Comment by worker767424 | Hacker News Reader

How is it that we vaccines we're confident are effective, but haven't been able to draw a conclusion on this, yet?

The vaccines are extremely effective so it's easy to see that in studies. It's harder to determine the difference between a small effect and no effect. If vitamin d was as effective as the vaccines we would certainly know by now. (It's fairly likely that it's just a spurious correlation by now, but it's hard to completely rule out the possibility that vitamin d has any effect.)

“Relative risk reduction and absolute risk reduction measures in the evaluation of clinical trial data are poorly understood by health professionals and the public. The absence of reported absolute risk reduction in COVID-19 vaccine clinical trials can lead to outcome reporting bias that affects the interpretation of vaccine efficacy. The present article uses clinical epidemiologic tools to critically appraise reports of efficacy in Pfzier/BioNTech and Moderna COVID-19 mRNA vaccine clinical trials. Based on data reported by the manufacturer for Pfzier/BioNTech vaccine BNT162b2, this critical appraisal shows: relative risk reduction, 95.1%; 95% CI, 90.0% to 97.6%; p = 0.016; absolute risk reduction, 0.7%...”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7996517/

Absolute risk reduction is naturally going to be low in vaccine trials if we don't intentionally infect all the participants with covid-19.

I get the need for the absolute risk reduction number but it would seem to me the only way to find that is to know how many who've been vaccinated have been exposed to the virus afterwards, or to purposely expose them.

It would seem that could take some time to get accurate results for the general population. And then we also have the variants of the virus to deal with too.

Finally, I don't have any real perspective on the "absolute risk reduction, 0.7%" number in relation to other vaccines. It sounds very low, but the article doesn't offer comparisons to other vaccines.

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