Is It Cold, Flu or COVID?

The flu is caused by influenza viruses and COVID-19 is caused by a coronavirus known as SARS-CoV-2. The common cold can be caused by a number of different viruses, though rhinoviruses are usually to blame, according to the Centers for Disease Control and Prevention (CDC).

While some people may lose their sense of taste and smell with a cold or the flu, it’s pretty rare, according to the National Institutes of Health. However, the symptom is common with COVID-19.

Though a stuffy or runny nose is most common with a cold or COVID-19, it’s also a symptom of the flu, the CDC says.

Vaccines are available for the flu and for COVID-19, but not for the common cold. If you haven’t had your flu shot yet, doctors say it’s not too late. And health officials are encouraging everyone who is eligible for the more recently updated COVID-19 boosters to get the shot.

The Food and Drug Administration has authorized several at-home COVID-19 tests, but flu tests and other tests that check for viral infections are usually done in a doctor’s office. If you have symptoms of COVID-19, it’s important to test, since you may be eligible for treatments if you are positive. If you’re negative, your doctor may want to test you for flu.

Diarrhea is not a common sign of flu in adults (it is in kids, though), nor does it usually accompany a cold.

Flu symptoms usually come on suddenly, according to the CDC. But it can take a few days before you start feeling the effects of a cold or COVID-19.