A multinational team including the University of Cambridge (UK), South Africa has established that even though the Omicron variant has gained exceptional immune evasion properties but also a much lower propensity to enter cells such as those in lung alveoli, resulting in its reduced pathogenicity.
They say "Omicron spike has higher affinity for ACE2 compared to Delta as well as a marked change of antigenicity conferring significant evasion of therapeutic monoclonal and vaccine-elicited polyclonal neutralising antibodies after two doses. mRNA vaccination as a third vaccine dose rescues and broadens neutralisation. Importantly, antiviral drugs remdesivir and molnupiravir retain efficacy against Omicron BA.1. Replication was similar for Omicron and Delta virus isolates in human nasal epithelial cultures. However, in lower airway organoids, lung cells and gut cells, Omicron demonstrated lower replication. Omicron spike protein was less efficiently cleaved compared to Delta."
To summarize - The Omicron variant has gained immune evasion properties, but at the same time compromised cell entry in TMPRSS2 expressing cells (primarily those in alveoli), as well as the ability to form syncytia or cell fusion – a combination characteristically linked to reduced ability to cause a severe disease.
They say "Omicron spike has higher affinity for ACE2 compared to Delta as well as a marked change of antigenicity conferring significant evasion of therapeutic monoclonal and vaccine-elicited polyclonal neutralising antibodies after two doses. mRNA vaccination as a third vaccine dose rescues and broadens neutralisation. Importantly, antiviral drugs remdesivir and molnupiravir retain efficacy against Omicron BA.1. Replication was similar for Omicron and Delta virus isolates in human nasal epithelial cultures. However, in lower airway organoids, lung cells and gut cells, Omicron demonstrated lower replication. Omicron spike protein was less efficiently cleaved compared to Delta."
To summarize - The Omicron variant has gained immune evasion properties, but at the same time compromised cell entry in TMPRSS2 expressing cells (primarily those in alveoli), as well as the ability to form syncytia or cell fusion – a combination characteristically linked to reduced ability to cause a severe disease.
