I've read that SARS-Cov-2 has several variants, e.g.:

When does one decide to refer to a virus as a new variant?

My research:

  • 1
    $\begingroup$ For those looking at the SARS-CoV-2 phylogenetic tree it is mainly about how lineages (becomes a clade once large enough) grow, propagate from locations and locations and split in sublineages. Sometimes one lineage deserves attention not only because of its growth but also because of its mutations, this was the case for the summer variants bearing spike and RBD mutations. 501Y.v1 & 501Y.v2 emerged in this context bearing most of the interesting features spotted in the summer variants: many spike mutations and deletions, long branch/accelerated evolution, exponential growth. $\endgroup$
    – reuns
    Jan 30, 2021 at 9:52

1 Answer 1


We use them as synonyms. However, variant is, in my view, more colloquial than scientific. Strains are in the literature often defined by their distinct genome compared to other strains of the same species (might be one base-pair substitution or more). In microbiology, including viruses, we often think of a strain as the proliferation of a single distinct DNA/RNA molecule.



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