A study from the Karolinska Institutet in Sweden shows that the coronavirus variant BA. 2. 75. 2, a sublineage of Omicron, largely escapes neutralizing antibodies in the blood and resists several monoclonal antiviral treatments. The findings, published in the journal The Lancet Infectious Diseases, suggest an increased risk of SARS-CoV-2 infections this winter, unless new and updated bivalent vaccines help boost immunity in the population.
While antibody immunity did not pass completely, BA. 2. 75. 2 showed much more dramatic resistance than the variants we studied in the past, largely driven by two mutations in the obligate receptor domain of the spike protein.
The study shows that antibodies in random serum samples from 75 blood donors in Stockholm were only one-sixth effective at neutralizing BA. 2. 75. 2 to the now-dominant variant BA. 5. Serum samples were collected 3 times: last November a year before Omicron emerged, in April after a giant wave of infections in the country, and from last August to early September after the BA. 5 variant became dominant.
According to the study, only one of the clinically available monoclonal antibody remedies that were tested, bebtelovicimab, was able to powerfully neutralize the new variant. .
BA. 2. 75. 2 is a mutated edition of some other variant of Omicron, BA. 2. 75. Since it was first discovered this fall, it has spread to several countries, but so far it only accounts for a minority of recorded cases.
“We now know that this is just a constellation of emerging variants with similar mutations that will most likely end up dominating in the near future,” says Ben Murrell, adding that “we expect infections to accumulate this winter. “
A few questions remain. It’s unclear whether those new variants will lead to higher hospitalization rates. In addition, although existing vaccines have generally had a protective effect against severe disease for Omicron infections, it is not yet known to what extent COVID vaccines will offer coverage opposite to these new variants to date. “We hope they’ll be beneficial, but we don’t yet know to what extent,” Murrell said.
The study was conducted in collaboration with researchers from ETH Zürich in Switzerland and Imperial College London in the UK.
The investment provided through SciLifeLab, the Erling-Persson Foundation, the European Union’s Horizon 2020 curriculum and innovation. Daniel J. Sheward, Gunilla B. Karlsson Hedestam and Ben Murrell have rights to intellectual assets related to antibodies that neutralize Omicron variants.
Karolinska Institute
Sheward, DJ, et al. (2022) Omicron subline BA. 2. 75. 2 exhibits evasion of neutralizing antibodies. Infectious diseases of Lancet. doi. org/10. 1016/S1473-3099(22)00663-6.
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