Face masks considerably reduce transmission of COVID
https://www.iza.org/publications/dp/13319/face-masks-considerably-reduce-covid-19-cases-in-germany-a-synthetic-control-method-approachPrevious studies to the contrary have been retracted; the simple and obvious good advice is to WEAR A MASK
https://www.acpjournals.org/doi/10.7326/L20-0745A homemade mask using high-thread count cotton catches 70% of virus particles; adding a layer of silk bumps up to 90%
https://www.preprints.org/manuscript/202006.0132/v1