This post is informational only.
Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine
NEJM article on Covid vaccine
The Pfizer Covid 19 vaccine results were reported in the New England Journal of Medicine as 95% effective. This is relative benefit not absolute benefit.
There were 40,000 volunteers in the study, ~20,000 receive the vaccine and ~20,000 received the placebo.
In the placebo arm 162 volunteers developed signs and symptoms of COVID-19 and tested positive. In the vaccine arm this number was eight.
Of the 162 in the placebo group nine were considered severe. Of the eight in the vaccine group one was considered severe. No one in either arm died. There was no mention of hospitalization in those with severe disease in the NEJM article.
162/20,000 = 0.81% Placebo arm
8/20,000 = 0.04% vaccine arm
0.04/.81 = ~5% => ~95% efficacy or effectiveness = relative benefit
0.81%-0.04 = less than 1% absolute benefit
The difference between relative benefit and absolute benefit is best expressed by NNT or number needed to treat to prevent one case.
162/8 = ~20 = NNT.
To put this in perspective, the NNT for flu shot on average is at least 40.
The NNT for vitamin D during the winter is about 4.
Of course vitamin D is effective not only for COVID-19 AND the flu but also any viral respiratory illness.
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www.afibbers.org]
Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data (meta-analysis of 15 studies published in 2017)
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www.bmj.com]
Edited 2 time(s). Last edit at 12/22/2020 10:58AM by PC, MD.
