Our new BMJ paper:
It& #39;s time to apply the precautionary principle to face masks

https://www.bmj.com/content/bmj/369/bmj.m1435.full.pdf">https://www.bmj.com/content/b...
@HWWPotts you dad& #39;s in here
You can follow @trishgreenhalgh.
Tip: mention @twtextapp on a Twitter thread with the keyword “unroll” to get a link to it.

Latest Threads Unrolled: