H3N2 influenza

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Recently, the Health Ministry confirmed that at least two people have succumbed to the H3N2 subtype of seasonal influenza in India.

About H3N2 influenza:  

  • Influenza A H3N2 is a seasonal virus and the occurrence of influenza infections normally peaks during season changes.
  • Symptoms- Fever, body ache, sore throat, cough, runny/blocked nose and a few shortness of breath.
  • It can spread from person to person and while anyone can get infected- older, adults and younger children are at a higher risk from H3N2.
  • The method of testing for H3N2 is also similar to COVID-19 testing – RTPCR.
  • There is a vaccine for seasonal flu that also covers H3N2.

Seasonal influenza:

  • According to WHO, seasonal influenza is an acute respiratory infection caused by influenza viruses.
  • There are 4 types of seasonal influenza viruses, types - A, B, C and D. In which Influenza viruses A, B, and C can infect humans.
  • Influenza A viruses are further classified into subtypes according to the combinations of the hemagglutinin (HA) and the neuraminidase (NA), the proteins on the surface of the virus.
  • There are 18 different subtypes of HA, which are numbered H1 through H18. Similarly, there are 11 different subtypes of NA, numbered N1 through N11.


Q1) What is Hemagglutination?

Hemagglutination is a reaction that causes clumping of red blood cells in presence of some enveloped viruses, such as the influenza virus. A glycoprotein on the viral surface, namely hemagglutinin, interacts with red blood cells, leading to the clumping of red blood cells and the formation of a lattice.

Source: All about H3N2 virus: symptoms, prevention, and cure