Coronavirus disease 2019 (COVID-19) can cause many of the same symptoms as the common cold, seasonal allergies and the flu. So how can you tell if you have COVID-19? It may help to learn about the ...

The influenza virus hijacks human cells in the nose and throat to make copies of itself. (Dreamstime) The influenza virus hijacks human cells in the nose and throat to make copies of itself.

Q My wife started getting sick a few days before Halloween. We were worried that it was going to turn into a bad respiratory illness, but it stayed in her nose and throat. That’s a common cold, right?

Dear A.T.R.: Both colds and influenza (the "flu") are respiratory illnesses that are caused by viruses. Influenza is caused specifically by the influenza viruses, which come in two main types (A and B ...

Although symptoms overlap, there are some key differences. Flu, cold, and COVID-19 share symptoms but differ in severity and specific signs. Vaccinations lessen severity and risk of complications or ...