NEW YORK — An estimated 80,000 Americans died of flu and its complications last winter — the disease's highest death toll in at least four decades.

The director of the Centers for Disease Control and Prevention, Dr. Robert Redfield, revealed the total in an interview Tuesday night with The Associated Press.

Flu experts knew it was a very bad season, but at least one found the size of the estimate surprising.

"That's huge," said Dr. William Schaffner, a Vanderbilt University vaccine expert. The tally was nearly twice as much as what health officials previously considered a bad year, he said.

In recent years, flu-related deaths have ranged from about 12,000 to 56,000, according to the CDC.

Last fall and winter, the U.S. went through one of the most severe flu seasons in recent memory. It was driven by a kind of flu that tends to put more people in the hospital and cause more deaths, particularly among young children and the elderly.

The season peaked in early February and it was mostly over by the end of March.

Making a bad year worse, the flu vaccine didn't work very well. Experts nevertheless say vaccination is still worth it because it makes illnesses less severe and save lives.

"I'd like to see more people get vaccinated," Redfield told the AP at an event in New York. "We lost 80,000 people last year to the flu."

CDC officials do not have exact counts of how many people die from flu each year. Flu is so common that not all flu cases are reported, and flu is not always listed on death certificates. So the CDC uses statistical models, which are periodically revised, to make estimates.

Fatal complications from the flu can include pneumonia, stroke and heart attack.

CDC officials called the 80,000 figure preliminary, and it may be slightly revised. But they said it is not expected to go down.

The makeup of the flu vaccine has been changed this year to try to better protect against expected strains.

"We don't know what's going to happen, but we're seeing more encouraging signs than we were early last year," said Dr. Daniel Jernigan, a CDC flu expert.