AH3N2

H3N2 is a subtype of the influenza A virus. Influenza A viruses are known for their ability to cause widespread epidemics and pandemics. The H3N2 subtype is characterized by its hemagglutinin (H) and neuraminidase (N) surface proteins. Hemagglutinin is responsible for the virus's ability to bind to host cells, while neuraminidase helps the virus to release new virions from infected cells.

H3N2 viruses are a common cause of seasonal influenza in humans. They are found globally and can circulate throughout the year, though outbreaks are more frequent during the colder months in temperate climates. The virus is highly contagious and spreads through respiratory droplets produced when an infected person coughs, sneezes, or talks. Symptoms of H3N2 infection are similar to those of other influenza strains and can include fever, cough, sore throat, body aches, and fatigue.

Like other influenza viruses, H3N2 undergoes frequent genetic changes through antigenic drift and antigenic shift. Antigenic drift involves minor mutations in the genes that code for the surface proteins, leading to gradual changes in the virus. This is why seasonal flu vaccines are updated annually to match the circulating strains. Antigenic shift involves more significant changes, often through reassortment of genetic material between different influenza viruses, which can lead to new strains to which most people have little or no immunity, potentially causing pandemics. H3N2 has been responsible for several notable influenza seasons and remains a significant public health concern.