How can we distinguish normal flu from a COVID-19 infection?

Distinguishing between the common flu (influenza) and COVID-19 infection can be tricky because both illnesses share many overlapping symptoms. Here are some key points and differences to look out for.

Common symptoms include fever, cough, fatigue, muscle aches, sore throat, stuffy or runny nose, and headache. There are also some specific symptoms for COVID-19 such as loss of taste or smell and shortness of breath.

Loss of taste or smell is a common symptom of COVID-19, less common with influenza. Shortness of breath or difficulty breathing can also occur with influenza, but is more common and severe with COVID-19. Nausea, vomiting, and diarrhea can occur with both illnesses, but appear to be slightly more common with COVID-19.

The time from exposure to the virus to the onset of symptoms is often longer with COVID-19 (2-14 days) than with influenza (1-4 days). COVID-19 can be more severe and lead to pneumonia, respiratory failure, and other serious complications, especially in older adults and people with underlying health conditions.

Both diseases can have serious consequences for older adults, pregnant women, and people with chronic conditions, but COVID-19 appears to have a broader range of serious consequences. The only way to be certain of the diagnosis is through specific tests such as the PCR test for COVID-19. There is also a specific test for influenza.

Source: https://www.who.int/news-room/questions-and-answers/item/coronavirus-disease-covid-19-similarities-and-differences-with-influenza

Author: Prof. Dr. Dirk Devroey - Latest update: 2023-12-11 - Copyright: Clinifacts 2025