— The flu, caused by influenza viruses that are always changing, leads to fever, chills, cough, sore throat, runny nose, body aches, headaches and feeling tired. Flu symptoms tend to hit more quickly than cold symptoms, and can last anywhere from a few days to two weeks.

The CDC said respiratory Illnesses like COVID, flu and RSV are increasing in the U.S. with levels very high in Delaware. Here's where they're highest.

Here are some ways to prepare for this cold and flu season as four illnesses circulate the country at one time.