Yes.  And No.  Mouth-to-mouth breathing has been around since cardiopulmonary resuscitation was introduced, While it has always been taught and part of CPR it has never been said you must do mouth-to-mouth on victims you find.  Does it help or improve chances of survival, yes.  Is it risky and yucky, yes.  So with that said mouth-to-mouth is still taught and discussed, but it is emphasised by Absolute CPR that mouth-to-mouth is a decision to do reserved by the rescuer.  COVID-19 and its publicized contagiousness has changed the way everyone thinks about mouth-to-mouth.

Use your best judgment when deciding to do mouth-to-mouth on unknown victims.