The signs and symptoms of both diseases can range from no symptoms to mild or severe symptoms. Because COVID-19 and the flu have similar symptoms, it can be hard to diagnose which condition you have based on your symptoms alone. Testing may be done to see if you have COVID-19 or the flu.
Symptom
COVID-19
Flu
Nausea or vomiting
Sometimes
Sometimes (more common in children)
Diarrhea
Sometimes
Sometimes (more common in children)
Shortness of breath or difficulty breathing
Usually
Usually
New loss of taste or smell
Usually (early  often without a runny or stuffy nose)
Rarely