Table 1 The major SARS-CoV-2 variants
From: Insights into organoid-based modeling of COVID-19 pathology
WHO label | Omicron [118] | Delta [119] | Alpha [110] | Beta [120] | Gamma [121] |
|---|---|---|---|---|---|
Pango Lineage Code | B.1.1.529 | B.1.617.2 | B.1.1.7 | B.1.351 | P.1 |
First documented | November 2021 | May 2021 | September 2020 | May 2020 | November 2020 |
Country/Region | South Africa | India | United Kingdom | South Africa | Brazil |
Number of Mutations | 32 mutations on the spike protein | High | Approximately 23 | High | High |
Infectivity as compare to earlier variants | High | Twice more transmissible | 1.5 times more transmissible | 50% more transmissible | Estimated 1.7 to 2.4 times more transmissible |
Symptoms | Mild headaches for several days (preliminary indications of similar symptoms as other variants) | Mild headaches, fever, persistent cough, sore throat (Shares symptoms as the original virus) | Fever, shortness of breath, cough, fatigue, change of sense of taste/smell (shares symptoms as the original virus) | Mild headaches, fever, persistent cough, sore throat (Shares symptoms as the original virus) | Mild headaches, fever, persistent cough, sore throat (Shares symptoms as the original virus) |
Risk of Reinfection | High | High | High | High | High |
Vaccination Efficacy | mRNA- based [122] Adenovirus-based [123] Recombinant protein-based [124] Inactivated virus-based [125] | ||||
Potential Therapeutic Strategy | Blocking VOC entry | Targeting spike proteins via S1 Receptor-Binding Domain (RBD) affecting (e.g. Alpha variant) [126, 127] Using single-domains neutralizing antibodies against any of those targets such as Soluble human recombinant ACE2 (e.g., Alpha variant) [110] in kidney organoid model) [120] and human airway organoid model [121] Anti-RBD nanobodies isolated from llamas to neutralize RBD variants (All VOC) [122] Targeting host cell transmembrane protease serine 2 (TMPRSS2) by TMPRSS2 inhibitors (e.g., Camostat) [123], or A disintegrin and metalloprotease 17 (ADAM17) inhibitors [124] | |||
| Â | Interrupting VOC replication | RNA dependent RNA polymerase inhibitors (e.g., Remdesivir, GS-441524) (e.g., Alpha variant) [125] Cas13d-based Prophylactic Antiviral CRISPR Human Cells (PAC-MAN) strategy that target reserved regions such as nucleocapsid protein and RdRp in SARS-CoV-2 viral genome [126] | |||