The flu season is upon us, and if last year is any guide, it could be a bad one. Last year was one of the worst in recent history. .

For companies in the business of  helping people through their aches, pains, fevers, runny noses, and the rest, there is money to be made. But first you’ve got to find those people. To do that, companies are watching us. 

By one count, cases of the flu have doubled over the last week.

“We saw particularly sharp increases across some of the Gulf States in the south, like Texas, Louisiana, Georgia,” says Josh Gray with AthenaResearch, an arm of AthenaHealth.

AthenaHealth monitors how often the 16,000 physicians in its network diagnose patients with the flu. When there’s a spike, Gray blogs about it. 

For companies like Proctor and Gamble and Johnson and Johnson knowing that lots of people are coughing and sneezing in Georgia is gold.

“We’re seeing this more and more,” says Harvard epidemiologist John Brownstein, who also develops those public health surveillance systems for infectious disease. “We are seeing lots of companies using public health surveillance data as a tool to target marketing of their products.”

With the market for over-the-counter cold and flu remedies worth nearly $6 billion, companies are also mining data from Twitter and Facebook to track the sick.

AthenaHealth’s Gray says the idea is to get the right product to consumers at the right time.

“There is more data than ever before and it’s becoming easier and cheaper to analyze it to much more sophisticated level,” he says.

Gray says companies who can make sense of all this information — and act quickly — are going to profit.