What Pennsylvania should know about the new flu strain
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Illustration: Eniola Odetunde/Axios
This year's flu vaccine may offer less protection against a newly circulating strain, but health experts still urge Pennsylvanians to get vaccinated to limit severe illness and prevent outbreaks.
Why it matters: A new Influenza A (H3N2) variant, "subclade K," emerged over the summer, sparking fears that this year's flu vaccine may struggle against it because the strain wasn't circulating when the shots were developed.
- Health officials in Canada, Japan and the U.K. are already sounding the alarm as a new wave of outbreaks fills hospital beds, and it's now the most-reported flu virus in the U.S., per the CDC.
State of play: Seasonal flu activity has ticked up in recent weeks as more people gather indoors, but statewide cases remain low and the increase is typical for this time of year, Pennsylvania Department of Health spokesperson Neil Ruhland tells Axios.
The big picture: When the flu vaccine is well matched to circulating strains, it can reduce overall flu illness risk in adults by 40%-60%, per the CDC, and early research suggests that the current flu shot is 30%-40% effective in preventing hospitalization in adults, with stronger protection for children.
What they're saying: "Pennsylvanians getting their annual flu shot remains the single most effective way to protect themselves from severe illness, hospitalization, and death from the flu," even with the emergence of the new strain, says Ruhland.
Threat level: Symptoms are similar to the common flu, including a sore throat, runny nose, fever, cough and headaches, but experts say subclade K may cause more severe symptoms in older adults, children and people with chronic conditions or compromised immune systems.
Context: Flu season generally runs from October to April, often peaking in the months after the December holidays. How severe it gets varies each year, driven by factors like vaccination rates and effectiveness, social behaviors and more.
Flashback: The U.S. experienced the worst flu season since 2009 last year, leaving hundreds of thousands of Americans hospitalized.
The bottom line: The CDC and the Pennsylvania Department of Health recommend flu shots to people 6 months and older. Wash your hands, stay home if you're sick, and steer clear of anyone who is, they say.
- Track flu cases in Pennsylvania and Allegheny County using their online dashboards and find local vaccination sites here.

