With the comma bracketed by \b, that will only match if there are no spaces (or other non-word characters) either side of the comma. Ie. in this sentence;
this,that & this, that & this ,that & this , that"
only the first comma will be matched.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.