Table 1.
This table summarizes the characteristics of the new Variant of Concern (Omicron: BA.1) and its sub-lineages (BA.1.1, BA.2 and BA.3). Additionally, very brief information about vaccine efficacy and combined antibiotic potency against BA.1 and its respective sub-lineages is provided.
| Omicron and its sub lineages | Pango lineages | Molecular weight | No of mutations | Unique mutation | Remarks | Reference |
|---|---|---|---|---|---|---|
| Omicron (BA.1) | B.1.1.529.1 | 141,328.11 | 39 | – | BA.1 is more likely to infect and reproduce in the upper respiratory tract than delta variant, whereas delta is more likely to infect and multiply in the lower respiratory tract. Early results revealed that the two-dose COVID vaccination schedule was less effective than prior variations against milder sickness caused by BA.1. It has been discovered that administering a third “booster” dose provides higher protection. Ronapreve (a monoclonal antibody combination of casirivimab and imdevimab) was reported to have decreased efficacy against BA.1. Another antibody therapy, sotrovimab, seems to retain anti-BA.1 spike protein action. The antiviral molnupiravir was also found to retain activity against BA.1 in six preclinical tests; however clinical trials have not yet been conducted. | [48,49] |
| BA.1.1 | B.1.1.529.1.1 | 141300.09 | 40 | One (R346K) | S309 (the precursor of sotrovimab), which has been shown to have lower neutralizing activity against omicron/BA.1.1. The combination of REGN10987 and REGN10933 (marketed as casirivimab) inhibited omicron/BA.2 but did not inhibit omicron/BA.1 or omicron/BA.1.1. | [50,51] |
| BA.2 | B.1.1.529.2 | 141,185.78 | 31 | Eight (T19I, L24del (deletion), P25del, P26del, A27S, V213G, T376A, R408S | The UKHSA's preliminary investigations showed no evidence that COVID vaccines were less effective against symptomatic disease when compared to BA.1. For, BA.2 vaccination efficacy against symptomatic infection was reported to be 13% at least 25 weeks after two doses (versus 9% for BA.1). This jumped to 70% two weeks following a third booster dose (versus 63% for BA.1). | [48] |
| BA.3 | B.1.1.529.3 | 140900.61 | 34 | One (R408S) | Some researchers have hypothesized that the reason for BA.3's delayed spread may be due to the fact that it does not contain the six extra mutations that BA.1 does. Best of our knowledge nothing is yet know about COVID vaccine effectiveness against this omicron sub-variant. | [46] |