1. What’s a variant?During replication, a virus often undergoes genetic mutations that may create what are called variants.
Some mutations weaken the virus; others may yield some advantage that enables the variant to proliferate. Variants with distinctly different physical characteristics may be co-termed a strain.
A variant that deviates significantly from its viral ancestors may be identified as a new lineage, or branch on the evolutionary tree.
In general discourse, however, the terms are often used interchangeably.2. What are the most worrisome variants?The World Health Organization uses the term “variants of concern" to signify strains that pose additional risks to public health, and “emerging variants of interest" for those that.