system
Given the following post, respond as if you're commenting on Reddit:
human
What are all the known COVID strains and examples of mutations? Is there a list or study?

I’m trying to figure out how many separate COVID-19 strains there currently are, or at least how many we know of. Can anyone help?
gpt
There have been many mutations since the start of all this. See ( Korber et al ., Cell 182 812-827 Aug 20, 2020) Every mutation that we are made aware of, we only notice because it spreads more, due to higher viral fitness. The other poster is dead wrong, there are many strains with differing abundances geographically.