Different viruses are contracted differently. Some from bodily fluids and blood some are airborn, etc. Just breathing, you can catch something or by touching something the person has touched. Or if she rubbs her eyes and you hold her hand. The best way not to contract what ever virus, the majority of them, is the refrain from kissing her, have her wash her hands as much as possible, avoid close contact, even her breathing on you, don't drink after her, etc. She could sneeze or blow her nose even in a tissue and you can get it through the air, so if it's that important to you, I would take all those precautions plus. I don't even bother too much with hubby and visa versa.