If someone is sick with a cold flu or fever but on medicine are they still contagious?

Still Contagious Yes, fever is a sign of being contagious. The medication is most likely an antibiotic and it takes a few days before it actually starts working.

Actually if it is a cold or flu it is viral and antibiotics should NEVER be given for these as they have no effect on viruses, can cause increased antibiotic resistance in bacteria, and are a complete waste of money.