08/01/2022
The data on Omicron is still too sparse to allow us to make clear predictions on the exact nature of this new variant, but we know enough about this strain to understand its essential meaning. Omicron is sending a message, loud and clear: this virus is capable of far more changes and far more variation than most ever thought possible and it will keep coming back to haunt us again and again.
From an evolutionary biology point of view, Omicron was to be expected. Coronaviruses in general have adapted to develop a wide variety of strategies to continue their replication and to infect and reinfect multiple species over millions of years. Coronaviruses evolved in bats and other long-lived, highly immunocompetent creatures. To survive, the virus had to learn a wealth of tricks — dampening immunity, evading early immune defenses, and shapeshifting to allow for multiple reinfections. Bats, in behavior at least, are a species quite similar to humans, living in densely packed communities but able to travel from one community to another, interacting with other animals and species along the way. Coronaviruses have learned how to thrive not only in a host species but how to infect neighboring species as well
At least seven coronaviruses have made the jump from animals to humans, but SARS-CoV-2 has shown that it can make the jump back into animals to reemerge and invade us again — a process called reverse zoonosis. But that’s not all this virus can do. If we look closely at the genomes of the coronaviruses that have emerged from bats and other species, we see that these viruses can readily recombine amongst each other, in addition to the point mutations we have seen in Omicron and in other known SARS-CoV-2 variants. Recombination, we know from influenza, can lead very quickly to much more virulent variants by picking up components that our immune systems have not previously seen.
