
09/04/2025
Is It Flu, COVID-19, Allergies, or a Cold?
Feeling sick can be especially concerning these days. Could your sniffles be caused by COVID-19? Or the flu? A cold? Or maybe allergies?
Determining the cause of an illness can be tricky because many share some symptoms. They can leave you sniffling, coughing, and feeling tired. But there are important differences.
Figuring out what’s making you sick can help you recover and prevent spreading sickness to others.
“Distinguishing COVID from flu can be difficult because the symptoms overlap so much,” explains Dr. Brooke Bozick, an NIH expert on respiratory diseases that affect the lungs.
Flu and COVID-19 are caused by different viruses that can be spread among people. Flu is caused by the influenza virus. COVID-19 is caused by SARS-CoV-2. Both can give you a fever, cough, headaches, and body aches.
Feeling sick? Learn the difference between COVID-19, allergies, and other viruses.