Two more lab groups—one from Sweden’s Karolinska Institute and the other from Harvard University—have reported results of antibody neutralization lab experiments, which suggest vaccination or previous infection offer some protection against the highly mutated BA.2.86 SARS-CoV-2 variant.
In other developments, countries uploaded more BA.2.86 samples to genetic sequencing databases, and the United Kingdom updated its assessment of the variant.
Encouraging neutralization findings
The first BA.2.86 sequences were reported a few weeks ago, and the variant’s high number of mutations signaled the biggest jump since the Omicron variant emerged following Delta variant circulation. Several scientists worried that the large magnitude of the change could allow BA.2.86 to easily evade earlier antibody protection from the vaccine or infection.
Last week, a group from Peking University reported the first lab studies on neutralization, which suggested that BA.2.86 had the capacity to escape antibodies from earlier XBB infection, but appeared to have lower infectivity than XBB.1.5 and EG.5 subvariants.
On September 1, the Karolinska Institute team reported its initial data from tests using the blood of donors from Stockholm, one cohort from before XBB circulated and the other after XBB arrived. On Twitter, Ben Murrell, PhD, with the Karolinska Institute, said the pre-XBB samples were poor at neutralizing BA.2.86 and didn’t fare much better against XBB.1.5. “But, somewhat encouragingly, last week’s samples were substantially better, with 8 out of 12 neutralizing BA.2.86 at titers over 100.”
The team also screened some monoclonal antibodies, finding that BA.2.86 was resistant against all of them, including sotrovimab.