If it has been going around then he may have had reason to suspect that is what it was. But it's one of those things where you do have to test for it to rule it out. FWIW, several years ago DD2 was dreadfully sick with this cough/cold that would make her vomit after a coughing session and I took her to the Dr when it wasn't clearing within what I thought was a normal period of time for a bad cold and starting to think it may have been WC because of the vomiting. It turns out it was actually pneumonia. It took about 6weeks to clear and 8 weeks before she was herself again.