Table 2.
General characteristics of the SARS-CoV-2 variants of concern (VOC) as of 31 December 2021 by the World Health Organization.
| WHO Label | Pango Lineage | GISAID Clade | Nextstrain Clade | Origin of First Samples Detected |
Date of First Documented Case | VOC Designation Date | Transmissibility | Clinical Severity | Clinical Response to Anti-SARS-CoV-2 Vaccines |
|---|---|---|---|---|---|---|---|---|---|
| Alpha | B.1.1.7 | GRY | 20I (V1) | United Kingdom | sept-20 | 18-12-2020 | Higher than previous variants (virological and epidemiological evidence) | Possibly similar incidence of severe COVID-19 and death (epidemiological studies with mixed results) | Vaccines prevent infection and adverse events |
| Beta | B.1.351 | GH/501Y.V2 | 20H (V2) | South Africa | sept-20 | 18-12-2020 | Higher than previous variants (virological and epidemiological evidence) | Possibly similar incidence of severe COVID-19 and death (epidemiological studies with mixed results) | Vaccines prevent infection and adverse events (possibly less effective in preventing infection) |
| Gamma | P.1 | GR/501Y.V3 | 20J (V3) | Brazil | nov-20 | 11-01-2021 | Higher than previous variants (virological and epidemiological evidence) | Possibly similar incidence of severe COVID-19 and death (epidemiological studies with mixed results) | Vaccines prevent infection and adverse events (possibly less effective in preventing infection) |
| Delta | B.1.617.2 | G/478K.V1 | 21A, 21I, 21J | India | oct-20 | 11-05-2021 * | Much higher than previous variants (virological and epidemiological evidence) | Increased incidence of severe COVID-19 and death (virological and epidemiological evidence) | Vaccines prevent infection and adverse events (slightly lower efficacy in preventing infection) |
| Omicron | B.1.1.529 BA.1 # | GRA | 21K, 21L, 21M | South Africa | nov-21 | 26-11-2021 ** | Extremely higher than previous variants (virological and epidemiological evidence)—higher than lineage B.1.617.2 | Preliminary data suggests that it has a lower incidence of severe COVID-19 and death—lower than lineage B.1.617.2 | Preliminary data suggest that vaccines prevent infection and adverse events (possible lower efficacy versus other VOCs) |
* Initially designated as VOI (04-04-2021); ** Initially designated as VUM (24-11-2021); # Change of classification proposed by the Pango Network to differentiate from the BA.2 sublineage (without del69-70).