Keep your questions coming on, Twitters or Dr Jen is back, and so many are asking.

With cold and flu season here, how do you know the difference?

How do you know when to call your doctor about possible corner?

Sometimes the symptoms can overlap, David, but look at this list.

It's fever over 100.4.

Cough, fatigue, shortness of breath, body aches.

Remember, they can be mild, so if you're concerned, you want to call your doctor.

But the key thing, because we see this on Twitter a lot, that fever it's 100.4 exact that swimming or higher.

Hi, everyone.

George Stephanopoulos here.

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