This year's flu season on track to be as bad as the last pandemic
Flu may have peaked but is still widespread across the U.S.
Kilian Daugherty, 1, is prepped for a chest X-ray by radiology technologist Kerah Adams as he's examined for flu symptoms at Upson Regional Medical Center in Thomaston, Georgia on Feb. 9, 2018.David Goldman / AP file
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It’s still not entirely clear why this season has been such a bad one in the U.S., Schuchat said. The H3N2 virus had predominated, and when that happens, there is usually a worse than usual epidemic, she said.
“It’s just one of those continuing questions with influenza,” Schuchat said.
“Every year is different.” Factors such as humidity and travel patterns can affect the spread of influenza, and it’s not fully understood.
Earlier this week, the National Institute of Allergy and Infectious Diseases released a strategic plan for developing a better flu vaccine that points out that scientists still really don’t know a lot about how influenza spreads.
“Our understanding of transmission of both seasonal and pandemic influenza is inadequate,” it says.
There’s growing evidence that age matters a lot. The first flu virus that someone is exposed to whether through infection of vaccination, may shape their immune system response to future infections.
"The vaccine worked pretty well in children so there are probably other factors at play. Some people wonder whether prior immune experience plays a role," Schuchat said.
Having a less-than-optimal flu vaccine doesn’t help. This season’s vaccine has only provided about 36 percent protection against flu. However, since fewer than half of Americans usually get a flu vaccine, it’s difficult to blame a bad flu year on a mediocre vaccine.
“We do know that the vaccine is worth getting,” Schuchat said. “Any protection is better than none.”
And federal officials are looking for more details on whether one vaccine type is better than another, but Schuchat said there is not enough information yet to make recommendations.
People are getting sick with various strains of flu. This week’s CDC flu report shows that about half of people tested for influenza had an influenza B strain.
Schuchat said there’s been greater demand for antiviral drugs to treat flu this year. Three drugs on the market — oseltamivir, zanamivir and peramivir — can reduce the severity and length of illness if people get them fast enough.