There appears to be something to the theory that BCG (TB) vaccination provides immunity to COVID-19.
This is out-of-the-box thinking! Researchers in the Netherlands are testing BCG vaccine against #COVID19 as it may work to boost immunity to viruses in general! Could explain why we are seeing far fewer cases in Africa, Middle East and South Asia https://t.co/XD2QwZSSqW
— Hina Chaudhry, MD (@Hinaheartdoc) March 26, 2020
The clinical trial mentioned in the tweet above could take a long time. Since proving causation from a mere correlation is a giant leap.
However, if there is enough data to prove a strong R square for the regression between people with BCG vaccination and immunity to COVID-19 it might be enough to “prove” the causation via hypothesis test with reasonable degree of certainty.
Not too different from how most drugs are approved for specific purposes by the FDA.
Establishing causation conclusively by turning the problem on and off as is done in engineering problem solving, or should be I should say, is simply not possible in most medical issues.
Now there are situations where such conclusive proof is elusive even in the engineering world. The hypothesis test with 95% confidence level is quite adequate for most situations.
When it isn’t, it is still possible to fail safe the system via multiple redundant backup systems.
Like in an aircraft for example. However, even that can fail.
Case in point is Boeing 737 max MCAS fiasco.
Soon to be seen in the “full self drive” cars…