NEW YORK — Three months ago, this flu season was shaping up to be short and mild in the U.S. But a surprising second viral wave has made it the longest in 10 years.
Some experts likened the unusual double waves to having two different flu seasons compressed, back-to-back, into one.
“I don’t remember a season like this,” said Dr. Arnold Monto, a University of Michigan researcher who had been studying respiratory illnesses for more than 50 years.
The previous longest recent flu season was 20 weeks, which occurred in 2014-2015.
Flu can cause a miserable, relatively mild illness in many people and a more severe illness in others. Young children and the elderly are at greatest risk from flu and its complications. Flu vaccinations are recommended annually for all but the very young.
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The current season began the week of Thanksgiving, a typical start time. At the beginning, most illnesses were caused by a flu strain that tends not to cause as many hospitalizations and which is more easily controlled by vaccines.
But in mid-February, a nastier strain started causing more illnesses and driving up hospitalizations.
Still, this flu season is not nearly as bad as last winter’s 19-week season, the deadliest in at least four decades. An estimated 80,000 Americans died of flu and its complications last season.
The CDC is estimating that flu-related deaths this season in the range of 35,000 to 55,000.
More good news: Brammer said that although the virus is notoriously unpredictable, signs suggest this flu season should be over soon.
“It’s on the verge” of being over, she said. “If nothing changes.”