Because it can catch another germ or virus
People may experience:
Behavioral: compulsive behavior, agitation, compulsive hoarding, hypervigilance, impulsivity, meaningless repetition of own words, repetitive movements, ritualistic behavior, social isolation, or persistent repetition of words or actions
Mood: anxiety, apprehension, guilt, or panic attack
Psychological: depression, fear, or repeatedly going over thoughts
True, they must drive with someone who is 21 years or older.