We are gradually understanding, and coming to terms with the SARS-CoV-2 virus causing the COVID-19 pandemic. We understand the virus is of the same family as the influenza ones we have learned to live with. However, these are constantly changing in two ways. We therefor decided to research how flu viruses drift and shift their personas and this is what discovered.
Flu Viruses Drift and Shift Their Personas in Two Ways
Influenza viruses – and we are learning COVID-19 ones too – are constantly evolving through antigenic drift, and shift according to Centers for Disease Control. Antigenic drift involves small step changes that affect the proteins on the surface of influenza viruses.
These changes reduce the ability of antigens in our immune system to take decisive action. Many influenza vaccines work at this level. That’s because antigenic drift produces closely-related viruses with similar antigenic properties.
As a result, the immune system can still recognize the influenza virus through a mechanism virologists call cross protection. However, while flu viruses drift and shift their personas our immune systems progressively become less effective. This is why influenza can come back time and time again.
But, Viral Antigenic Shift Is a Another Matter
But antigenic shift is more radical than antigenic drift. That’s because it is an abrupt, major step change to an influenza virus that generates new proteins. This can create a new influenza sub-type that our immune system is unable to recognize.
Antigenic shift can occur when an influenza virus ‘jumps across’ from an animal to the human species. As happened when swine viruses spread quickly, and caused epidemics against which humans had no natural immunity.
Flu viruses drift and shift their personas organically in the greater order of things. We are learning something similar is happening with the SARS-CoV-2 virus causing the COVID-19 disease. Perhaps this is why we will require regular re-vaccination. Only time will reveal the whole truth.
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Preview Image: Time-line of Paleoviruses
