Table 1.
Classification of SARS-CoV-2 variants of the WHO Technical Advisory Group on Virus Evolution.
| Variant of Interest (VOI) | Variant of Concern (VOC) | Variant Under Monitoring (VUM) | Former Monitored Variant | |
|---|---|---|---|---|
| World Health Organization working definition |
1. SARS-CoV-2 variant with genetic changes that are predicted or known to affect virus characteristics such as transmisibility, disease severity, immune escape, diagnostic and therapeutic escape. 2. Identified to cause significant community transmission or multiple COVID-19 clusters, in multiple countries with increasing relative prevalence alongside increasing number of cases over time, or other apppernt epidemiological impacts to suggest and emerging risk to global public health. |
1. SARS-CoV-2 variant that meets VOI criteria. 2. Associated with one or more of the following characteristics of global public health relevance: (a) Increase in transmisibility or detrimental change in COVID-19 epidemiology. (b) Increase in virulence or change in clinical disease presentation. (c) Decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics. |
SARS-CoV-2 variant with genetic changes suspected to affect virus characteristics with a potential future risk, but unclear evidence of phenotypic or epidemiological impact. | Previous VOCs/VOIs/VUMs that have been reclassified on at least one of the following criteria: (a) The variant is no longer circulating at levels of global public health significance. (b) The variant has been circulating for a long time without any significant epidemiological impact. (c) Scientific evidence demonstrate that the variant is not associated with concerning properties. |
| Designed SARS-CoV-2 variants as of 31 December 2021 (Pango lineage) |
C.37 (Lambda variant) B.1.621 (Mu variant) |
B.1.1.7 (Alpha variant) B.1.351 (Beta variant) P.1 (Gamma variant) B.1.617.2 (Delta variant) B.1.1.529/BA.1 (Omicron variant) |
AZ.5 C.1.2 B.1.617.1 * B.1.525 * B.1.526 * B.1.630 B.1.640 |
AV.1 AT.1 P.2 * P.3 * R.1 B.1.466.2 B.1.1.519 C.36.3 B.1.214.2 B.1.427/B.1.429 * B.1.1.523 B.1.619 B.1.620 |
* Previously classified as VOIs, then reclassified as Variant Under Monitoring or Former Monitored Variant.