Published on: March 7, 2023

H3N2 Influenza

H3N2 Influenza

Why in news? Karnataka government had high-level meeting over H3N2 variant to discuss the spread of the H3N2 variant of Influenza A virus and to identify treatment methods for the infection, whose symptoms include persistent cough and fever.


  • The flu-causing H3N2 variant has been on the rise since December 2022, causing respiratory symptoms that are similar to Covid-19.
  • As per the reports of the National Centre for Disease Control, most of the cases of persistent cough, nausea, sore throat and other flu symptoms that are widespread in the country are because of the H3N2 virus.

About H3N2 Influenza

  • H3N2 influenza, also known as the “Hong Kong flu,” is a type of influenza virus that can cause respiratory illness in humans
  • Influenza A virus subtype H3N2 (A/H3N2) is a subtype of viruses that causes influenza (flu) that is most important cause of human influenza.
  • H3N2 viruses can infect birds and mammals and the virus has mutated into many strains.
  • It is highly contagious and can spread from person to person through droplets generated when an infected person talks, coughs, or sneezes.
  • It can also spread by touching a surface contaminated with the virus and then touching one’s mouth or nose.
  • People who are at high risk of complications from the flu include pregnant women, young children, older adults, and people with underlying medical conditions.
  • Separate vaccines are developed for the Northern and Southern Hemispheres in preparation for their annual epidemics.
  • In the tropics, influenza shows no clear seasonality.