I am writing my opinion only about showers and baths. I am not going to use any scientific evidence to support my belief because this is an opinion. I will use some common sense to answer this question. Here is my biased effort.
When I take a bath, I like to use very warm water with bubbles added for aroma and relaxation. That’s right! I am a manly man and like bubbles! Watching them foam and then burst is enjoyable. I forget about the cares my life. The warmth of the water comforts my muscles and soul, and allows me to recuperate. Ahhh!!! I can visualize and begin to feel the wonderful heat engulfing my body. Admit it! You too, this very moment are feeling the relaxing heat! Feels good does it not?
Baths are fabulous, but there is the lingering thought of the grime or dirt just floating around on the bubbles or sinking to the bottom of the tub. This filth just never disappears, even after you use your best smelling and highest dollar soap. When you arise from the liquid refreshed and glowing with warmth, some of the ugly particles remain attached to your energized body!
Ditch the antibiotics: By all means consult your doctor if the cold is associated with another infection, but don’t go thinking they can hand out cure-all pills. Colds are viruses and antibiotics don’t work on viruses.