More than 6 million Americans have already caught influenza this flu season, and as many as 80,000 have ended up in the hospital, federal health officials said Friday.

For the first time, the Centers for Disease Control and Prevention can provide real-time estimates of the impact of flu on the public. They show between 6 million and 7 million people have been infected with flu, 3 million or more have visited doctors because of flu symptoms and between 70,000 and 80,000 have been sick enough to have been hospitalized.

"This is the first year that we're actually reporting these numbers during the season, and going forward we're going to be reporting them every week," the CDC's Dr. Alicia Fry told NBC News.

So far, the flu season has not taken off like it did last year, when close to 50 million people caught flu and 80,000 died. It was the worst flu season in decades.

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Flu seasons vary from year to year and experts say they are almost impossible to predict. This year, the annual epidemic is unfolding more slowly than it did last year. “Flu activity nationally is elevated,” the CDC says in its latest report on flu.

"We do expect there to be several more weeks of flu," Fry said.

So far this year, 16 children have died from flu. The CDC counts the death of every child from influenza. Adult sicknesses and deaths are estimated.

Flu activity is elevated across the U.S., the CDC says. CDC

“Calculations are based on adjusted rates of laboratory-confirmed, influenza-associated hospitalizations collected through a surveillance network that covers approximately 8.5 percent of the U.S. population, or about 27 million people,” the CDC said. In the past, the CDC has waited until the end of the season to release estimates of how many people have been affected by flu.

Every year, influenza kills people. It varies a lot from year to year, but before last year, the CDC said seasonal flu kills between 12,000 to 56,000 Americans every year, depending on how rough the season is, and it puts 140,000 to 710,000 people into the hospital.

Last season went far beyond that. "It’s a little too early to know what’s going to happen with this flu season," Fry said.

The CDC recommends that just about everyone over the age of 6 months get a flu vaccine. Fewer than half of Americans ever do.

“It’s still not too late to get a flu vaccine. Year in and year out, people who get a flu vaccine are better off than people who do not get vaccinated,” the CDC said. “Flu vaccines reduce the risk of flu illness and serious flu complications that can result in hospitalization and have been shown to be life-saving in children.”

Fry said vaccine is still available. "I haven’t heard about shortages of flu vaccine from what I understand there is plenty of flu vaccine available so people should be able to find it," she said.

Quick treatment can save lives, the CDC said. There are several influenza medications on the market now. “People who are very sick or who are at high risk of serious flu complications and get flu symptoms should see a health care provider promptly for possible treatment with a flu antiviral drug,” the CDC said.