dancedancekj saidThe doctor with a cold or flu is probably much more sanitary than you are on any given day, so long as he's not sneezing or coughing directly into your face.
Wouldn't talking or laughing at a close distance also spray the bacteria/viruses into the air? If the patient is already ill, they probably don't appreciate a family physician treating their kid. As some here have said, they would leave. If it's a hospital, the admitted patient probably can't leave.
The other issue is how tired the doctor is. I don't want my doctor to be thinking "How soon do I get to go to bed?"
I wear a mask, which is even more efficient at keeping items in than it is keeping things out. I'm more at a risk of catching a disease the patient is carrying, than the patient is of catching something I have.
If the patient is ill enough to be seeing the doctor, a cold or flu shouldn't be on their lists of worries to be caught. If it's a physical, you're going to have minimal contact with the health care provider anyway.
That being said, it's the responsible thing to do to take the day off should you become moderately to severely sick with a cold or flu because you have the responsibility to project an air of sanitation and health in your place of business. Which is kind of bullshit, since you would be more likely to catch the cold from a fellow patient, a door handle, or going to the grocery store, but appearances must be maintained, and you'll probably recover more quickly if you take the day off.