Influenza, or the flu, is a contagious respiratory virus. It can be a severe illness that affects the nose, throat and sometimes lungs. Symptoms of influenza are sore throat, cough, congestion ...
Here's what to know about flusymptoms in 2025, how to tell if it's something else, and how to protect yourself: But there are some differences. COVID-19 can show up later than the cold or flu ...