Table 2.
A comprehensive list of the variants being monitored (VBM), including their origin, global distribution, vaccine efficacy level, and transmission phenomenon, serves as a critical reference tool for public health officials and researchers to track and screen the emergence and feast of new SARS-CoV-2 variants [65].
| WHO labels | Clade | First identified lineage | Top pangoline lineage | Origin | First infection | Vaccine activity against this | Transmission phenomenon |
|---|---|---|---|---|---|---|---|
| Alpha | 20I | B.1.1.7 | B.1.1.7 | Kent, England | November 20 | According to statements made by Pfizer, Moderna, and Johnson & Johnson, their respective vaccines have demonstrated effectiveness in protecting against severe disease and hospitalization associated with the Alpha variant. | 30%–50% more transmissible in comparison with the original SARS-CoV-2 strain |
| Beta | 20H | B.1.351 | B.1.351 | South Africa | July 20 | The Beta variant has been reported to exhibit lower susceptibility to the vaccines developed by AstraZeneca-Oxford, Pfizer-BioNTech, Moderna, and Johnson & Johnson. | The initial coronavirus strain was found to 50% less contagious in comparison with Beta variant. |
| Delta | 21A, 21I, 21J | B.1.617.2 | B.1.617.2 | India | October 5 20 | The 3 vaccines available in the United States have been deemed highly efficacious in protecting against severe illness, hospitalization, and mortality resulting from the Delta variant. However, despite their effectiveness, breakthrough infections of Delta have occurred in some individuals who were fully vaccinated. Moreover, vaccinated individuals who contracted the infection were still capable of transmitting the virus to others, although the period of their infectiousness was likely to be shorter. It is worth noting that no vaccine provides 100% protection against any variant of the virus. | The transmissibility of the Delta variant has been found to be significantly higher, estimated to be around 80–90% more contagious than the Alpha variant. |
| Delta Plus | 21A, 21I, 21J | AY.4.2 | AY.4.2 | UK | December 20 | Partially effective | 10%–20% more transmissible than Delta. |
| Omicron | 21K-L, 22A-F, 23A | BA.1 | BA.5, BF.7, XBB, BN.1, BF.11, BQ.1, BQ1.1 | Botswana and South Africa | November 21 | Experts are still learning about their effectiveness against the latest Omicron subvariants | The most transmissible variant of concern |