The thing about Omicron is that it has a very large number of really bad mutations: > The variant has a large number of mutations, of which some are concerning

The thing about Omicron is that it has a very large number of really bad mutations: > The variant has a large number of mutations, of which some are concerning.[8] 32 mutations affect the spike protein, the main antigenic target of antibodies generated by infections and of many vaccines widely administered. Many of those mutations had not been observed in other strains.[9][10] > The variant is characterised by 30 amino acid changes, three small deletions and one small insertion in the spike protein compared with the original virus, of which 15 are located in the receptor binding domain (residues 319-541). It also carries a number of changes and deletions in other genomic regions. Of note, the variant has three mutations at the furin cleavage site.[11] The furin cleavage site increases SARS-CoV-2 infectivity.[12] See https://en.wikipedia.org/wiki/SARS-CoV-2_Omicron_variant https://en.wikipedia.org/wiki/SARS-CoV-2_Omicron_variant The "receptor binding domain" is the portion of the spike protein that actually binds to the ACE2 receptor the virus uses to get into our cells. In contrast, Delta has 3 mutations in the RBD (https://asm.org/Articles/2021/July/How-Dangerous-is-the-Delta-Variant-B-1-617-2 https://asm.org/Articles/2021/July/How-Dangerous-is-the-Delt...) and it has 10 mutations affecting the spike protein (https://gvn.org/covid-19/delta-b-1-617-2/ https://gvn.org/covid-19/delta-b-1-617-2/)