Published: Tue, March 06, 2018
Medical | By Vernon Walton

Flu season worst since 2009, CDC says

Flu season worst since 2009, CDC says

But other indicators from the Centers for Disease Control and Prevention suggest that a vicious influenza season may finally be starting to plateau.

There are four species of influenza viruses - A, B, C, and D - and seasonal flu is caused by influenza A and B. Every year, different strains of these viruses circulate.

But there's another thing that researchers have recently come to realize also alters the vaccine's effectiveness: Whenever H3N2, a strain of the influenza A virus, is the dominant flu type in circulation, the vaccine doesn't perform as well.


- The Food and Drug Administration issued a warning today against being fooled by fraudulent or unapproved flu medications. "It's not typically the same all around, but I think this season seems a little bit more mixed", he said.

The Adams County Health Department said the number of flu cases is on the way down and hopes it continues.

The background to the discussion this year was "understanding that the vaccine hasn't really performed the way we would like in the last couple of seasons", he said.


Scientists want to create a flu vaccine that lasts a lifetime. "We're still faced with this challenge, this technical challenge of getting a H3N2 to match the circulating strains".

"That is what we anticipated", he said.

"Like previous seasons when H3N2 was dominant in the beginning of the season, we may see a late-season bump of influenza B", Nordlund said in an email.


Although no data is collected to indicate how many people receive flu vaccinations, Morrow said he believes that the low projected effectiveness rate of this year's vaccine - about 30-percent effective at preventing flu symptoms - has discouraged those who are innately wary of vaccinations. However, since fewer than half of Americans usually get a flu vaccine, it's hard to blame a bad flu year on a mediocre vaccine. The FDA requires that vaccines be grown in chicken eggs, but some strains, like this year's H3N2 don't grow well in eggs.

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