No person may walk about in public if he or she has the common cold.

RCW 70.54.050
Exposing contagious disease — Penalty.

Every person who shall wilfully expose himself to another, or any animal affected with any contagious or infectious disease, in any public place or thoroughfare, except upon his or its necessary removal in a manner not dangerous to the public health; and every person so affected who shall expose any other person thereto without his knowledge, shall be guilty of a misdemeanor.