In a new study from the University of Washington, researchers have identified antibodies that neutralize omicron and other SARS-CoV-2 variants.
These antibodies target areas of the virus spike protein that remain essentially unchanged as the viruses mutate.
The omicron variant has 37 mutations in the spike protein, which it uses to latch onto and invade cells. This is an unusually high number of mutations.
It is thought that these changes explain in part why the variant has been able to spread so rapidly, to infect people who have been vaccinated and to reinfect those who have previously been infected.
In the study, the researchers found the omicron variant spike protein was able to bind 2.4 times better than the spike protein found in the virus isolated at the very beginning of the pandemic.
They also found that the omicron version was able to bind to mouse ACE2 receptors efficiently, suggesting omicron might be able to “ping-pong” between humans and other mammals.
The researchers then found that antibodies from people who had been infected by earlier strains and from those who had received one of the six most-used vaccines currently available all had reduced ability to block infection.
Antibodies from people who had previously been infected and those who had received the Sputnik V or Sinopharm vaccines as well as a single dose of Johnson & Johnson had little or no ability to block—or “neutralize”—the omicron variant’s entry into cells.
Antibodies from people who had received two doses of the Moderna, Pfizer/BioNTech, and AstraZeneca vaccines retained some neutralizing activity, albeit reduced by 20- to 40-fold, much more than any other variants.
Antibodies from people who had been infected, recovered, and then had two doses of the vaccine also had reduced activity, but the reduction was less, clearly demonstrating that vaccination after infection is useful.
Antibodies from people, in this case, a group of renal dialysis patients, who had received a booster with a third dose of the mRNA vaccines produced by Moderna and Pfizer/BioNTech showed only a 4-fold reduction in neutralizing activity.
This shows that a third dose is really helpful against omicron.
The researchers also identified four classes of antibodies that retained their ability to neutralize omicron.
Members of each of these classes target one of four specific areas of the spike protein present in not only SARS-CoV-2 variants but also a group of related coronaviruses, called sarbecoviruses.
These sites on the protein may persist because they play an essential function that the protein would lose if they mutated. Such areas are called “conserved.”
The team suggests that designing new vaccines and antibody treatments could be effective against a broad spectrum of variants that emerge through mutation.
If you care about Omicron, please read studies about 5 steps to avoid Omicron, and findings that COVID vaccine booster increases protection against COVID, including Omicron.
For more information about COVID, please see recent studies about people with type 2 diabetes are hit harder by COVID-19, and results showing this COVID-19 vaccine can provide ‘border protection’ to the body.
The study is published in Nature. One author of the study is David Veesler.
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