I've read that SARS-Cov-2 has several variants, e.g.:
- Can the U.S. keep Covid variants in check? Here's what it takes.
- Novavax’s Vaccine Works Well — Except on Variant First Found in South Africa
When does one decide to refer to a virus as a new variant?
- I looked at https://biology.stackexchange.com/questions/tagged/variant?tab=Votes
- The question What determines when a virus becomes a “new strain”? addresses strain. Is strain the same as variant?