You may have heard the term H3N2 in the news or read about it online.
But H3N2 is a little different.
Flu Overview
H3N2 flu is a subtype of influenza A.
Illustration by Jessica Olah, Verywell
Although there aremultiple types of influenza, onlyinfluenza Ais further broken down into subtypes.
(Before 2024, quadrivalent vaccines would include two strains of influenza B.)
What Is the H3N2 Flu Virus?
H3N2 virus is a non-human influenza virus that normally circulates in pigs but can infect people.
Viruses that normally circulate in pigs are swine influenza viruses.
When these viruses infect humans, they are termed variant viruses.
The H3N2 virus was circulating in pigs in 2010 and was first detected in people in 2011.
H3N2 is not as severe as H1N1 but may be more severe than some other strains of flu.
However, that doesn’t mean it didn’t work at all.
They are most effective if taken within the first 48 hours of the onset of symptoms.
These vaccines only contain a protein portion of the virus.
It doesnt contain the tools needed for a virus to replicate itself.
Summary
H3N2 is one subtype of the influenza A virus that often causes significant illness.
Flu seasons are often more severe when H3N2 is the dominant strain causing illness.
Symptoms are similar no matter what strain of influenza is circulating each year.
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Centers for Disease Control and Prevention.Influenza A (H3N2) variant virus.
Oklahoma State Department of Health.Influenza A H3N2 variant (H3N2v).
LeMieux J.Some Bad Flu News: H3N2 Is A Major Player This Year.
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Centers for Disease Control and Prevention.Flu Symptoms & Diagnosis.
Centers for Disease Control and Prevention.Clinical signs and symptoms of influenza.
Centers for Disease Control and Prevention.Flu Treatment.
Centers for Disease Control and Prevention.Healthy habits to help protect against flu.
Centers for Disease Control and Prevention.Influenza (flu) vaccine safety.
