Most will not stop a stab but it will work just fine against a slash from a knife. It will be of no use against a sword since your primary targets for a sword are not covered by a vest. I own a slash resistant Polo style shirt from a company that makes a product called a "trust bag" and wear it when I go to latino bars.
Edit: This comment is in reference to a tag; every blade that I own is a molecular blade. I must also point out that every blade ever made has been one also. My taste in blades is pretty much confined to utilitarian ones although I do own a few Randall Made ones. The only true exotic I have ever owned was a very, very old katana that my grandfather won in single combat from its previous owner. My step brother stole it a longtime ago and pawned it somewhere in Ft Worth. He has since passed away (heavy meth use for nearly 30 years) and I have never recovered the katana.
True story, Odds are in the knife holders favor when under 20 feet,
I did not say knife; I said sword. Conventional Kendo/Kenjutsu/Iaido tactics involve "Dis-arming" your opponent and unlike hand gun wounds sword wounds cause death very, very quickly.
Edit: The normal draw, present, and fire techniques that are taught for actual fighting with a hand gun leaves you a sitting duck for anyone close to you that has a drawn sword and the skills and drive to use it. You will die plain and simple. If someone has a blade of any sort and you do not have your sights already on them and are firing at them your best bet is to increase the distance between you as quickly as possible. Charge a gun, run from a blade.
Why do y'all think the police get so damn trigger happy when they think someone has a blade? It is because they have had training that has very clearly demonstrated how dangerous a blade can be and know how little time they have available to them to react to it.
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