Is It Covid or the Flu? How to Tell Symptoms Apart

Covid and the flu share deceptively similar symptoms: coughing, full-body aches, fevers. Both illnesses can give you a runny nose, nausea, diarrhea, vomiting and shortness of breath; both can leave you fatigued, feeling worn out and depleted.

With BA.5, the dominant version of the coronavirus currently circulating in the United States, most people who are vaccinated will experience mild symptoms, said Dr. Peter Chin-Hong, an infectious disease specialist at the University of California, San Francisco. Many people will have a sore throat and cold-like symptoms. The flu is more likely to induce aches all over your body, Dr. Chin-Hong said. “You feel like you’ve been beaten up,” he said.

There are some symptoms that are unique to Covid, such as losing taste and smell, although people infected with BA.5 may be less likely to experience that.

Both Covid and flu can cause severe illness in older adults, people with underlying medical conditions and pregnant women.

The only reliable way to tell which infection you have is by testing, said Dr. Adam Ratner, a pediatric infectious disease specialist at N.Y.U. Langone. An at-home Covid test can quickly determine whether or not you have the virus, although testing too soon after infection can lead to false negatives. Experts advise taking a second rapid test 24 to 48 hours after the first, to ensure that the results are accurate. If you still have symptoms and are testing negative, you may want to take a P.C.R. test, which is more sensitive and, in some cases, can detect the virus earlier than a rapid test.

You should also get tested for the flu, Dr. Chin-Hong said, so that a doctor can prescribe a therapy like Tamiflu if you have the illness. “You can at least shave off one day of your misery,” he said. Some pharmacies and Covid testing sites offer two-in-one tests for both illnesses.