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Vaccines, XBB.1.5 variant and antibody evasion

Corona virus XBB and XBB.1 were first identified in India in mid-August and quickly became predominant in India.  The spike protein of the predominant XBB subvariant has 14 mutations in addition to those found in BA.2, including 5 in the N-terminal domain (NTD) and 9 in the receptor-binding domain (RBD), whereas XBB.1 has an additional G252V mutation.



Single and combination therapies with monoclonal antibodies have received emergency use authorization for COVID-19. 

Using COVID-19 pseudovirus, which enables the study of the SARS-CoV-2 virus in cell culture, XBB, and XBB.1 subvariants were found to have far greater antibody resistance than earlier variants. XBB sublineages are completely resistant to bebtelovimab, leaving us with no authorized antibody for treatment use.

The combination of mAbs known as Evusheld that is authorized for the prevention of COVID-19 is also completely inactive against the new subvariants. This poses a serious problem for millions of immunocompromised individuals who have weak response to COVID-19 vaccines. 

Even though it is spreading, there is no evidence that it causes more severe infection than any other Omicron variant.

We have to be more alert as XB.1.5 is better at evading the antibodies from COVID vaccines and previous infection 


References:

1. https://www.cell.com/cell/pdf/S0092-8674(22)01531-8.pdf?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867422015318%3Fshowall%3Dtrue

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