Concerns About the B.1.1.529 Covid Omicron Virus
Scientists are concerned because of the number and variety of mutations B.1.1.529 acquired — what Sharon Peacock, the director of the Covid-19 Genomics UK Consortium, called a “very unusual constellation of mutations.” Some mutations have been previously seen in other variants and are associated with increased transmissibility and the ability to get around immune protection.
Scientists can’t predict how different mutations will behave when combined, but of particular worry to scientists is that the virus has some 32 mutations in its spike protein, which is what vaccines teach our immune system to recognize and target.
The variant “has a very high number of mutations with a concern for predictive immune evasion and transmissibility,” said Tulio de Oliveira, director of the Center for Epidemic Response and Innovation, who helped identify the variant in South Africa.
What does it mean for immune protection?
If the spike protein changes, the antibodies elicited by vaccines or an earlier infection can’t recognize it as well. The more changes, the more foreign that spike starts to look to the immune system.
Vaccines generate what’s called a polyclonal response (see Polyclonal B cell response in vocabulary), with lots of antibodies that recognize different pieces of the spike protein. Other variants have had mutations that caused changes in a particular spot on the protein — called an antigenic site — and might have thrown off those corresponding antibodies, but there were plenty of other antibodies that still could recognize the virus.
With the new variant, it has so many changes across the spike protein nearly all the antigenic sites we know about are changed on this virus. This means we have a lot of unknowns to deal with. So we need to take extra precautions to protect ourselves until more is understood about this virus.