That is not true.
The SARS-CoV-2 virus is 0.12 microns, influenza 0.14 microns.
The droplets your cough & sneeze are larger than 5 microns. A surgical mask only stops particles larger than 5 microns.
And N95 mask, which has to be fitted, stops 95% of particles larger than 0.3 microns. So even the N95s really don’t “work” against COVID
Oops, you are correct - I meant to say that viruses are much smaller.