The World Health Organization (WHO) has defined a SARS-CoV-2 isolate as a variant of interest (VOI) if it is phenotypically changed compared to a reference isolate of has a genome with mutations that lead to amino acid changes associated with established or suspected phenotypic implications; AND has been identified to cause community transmission/multiple COVID-19 cases/clusters, or has been detected in multiple countries.
A VOI is further classified as a variant of concern (VOC) if, through a comparative assessment, it has been demonstrated to be associated with:
- Increase in transmissibility of detrimental change in COVID-19 epidemiology;
- Increase in virulence or change in clinical disease presentation; or
- Decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.
WHO-designated variants of concern (VOCs) and selected variants of interest (VOIs), as of 4 August 2021.