Both colds and influenza, the “flu,” are respiratory illnesses that are caused by viruses. Both can cause a fever, cough, runny nose and sore throat. However, the flu often causes muscle aches, which can be severe.

I’ve been lax lately in terms of my health. I admit it. While I haven’t been at music concerts among thousands of people or riding packed subway cars, I have been going to stores during the daytime when the aisles are full.