Flu activity varies by region but vaccine timing is key

Predicting flu activity is like predicting a storm, researchers said. You can't make predictions until you start to see activity. So as the storm builds or flu numbers build you can more accurately predict what comes next.

This year, Columbia researchers are using an algorithm Google came up with that looks at online searches related to flu to get a better sense of flu activity in specific local areas.

“The interesting thing is they can take that big data online search activity and estimate something the CDC (Centers for Disease Control and Prevention) gets and compiles and usually has to release with a week or two lag,” said Shaman.

Gretchen Hollett said she hasn’t heard of her daughter’s classmates staying home sick just yet.

“I don't think there's been very many who've been out of school who's had the flu,” said Hollett. “So I do think it's important to get the shot before the flu hits.”

Doctors say she's right on.

The flu shot takes two weeks in your system to offer the maximum defense.