Q&A #11: Animal reservoirs
Q&A with Geert Vanden Bossche
Attached are some recent papers on SARS-CoV-2 in mink, mice, rats, deer, lions, hamsters, cats, etc. There have also been headlines about hamsters in a Hong Kong pet store testing positive.
In one of your first letters, I recalled you saying: "It’s certainly also worth mentioning that mutations in the S protein (i.e., exactly the same protein that is subject to selection of escape mutations) are known to enable Coronaviruses to cross species barriers."
What is the role of this wide variety of animal reservoirs in the future of the pandemic? How significant are the selective pressures of these different host environments on the evolution of the virus? Is this something to be concerned about?
Animal reservoirs will increase the spectrum of highly infectious variants the virus can choose from when put under massive S-directed immune pressure. Omicron has already become largely resistant to S-directed immune pressure but mass vaccination against Omicron would of course revert that situation. The more variants exist (including animal-derived variants), the more readily the virus could select a variant candidate that is capable of rapidly* adapting to the vaccinated population upon the latter’s exposure to animal reservoirs.
* i.e., paying a relatively low fitness cost to resist S-directed immune pressure on Omicron