Flu 2024 Symptoms. Influenza (also known as “flu”) is a contagious respiratory illness caused by influenza viruses. Your healthcare professional will do a physical exam, look for symptoms of flu and possibly order a test that detects influenza viruses.
It can cause mild to severe illness, and at times can lead to death. If you get rsv, on the other hand, it may take 4 to 6 days before symptoms show.
