SARS-CoV-2 BA.2.86 is less resistant to vaccine, but may be a problem in the lung

New research shows that the recently emerged BA.2.86 omicron subvariant of the virus that causes COVID-19 can be neutralized by bivalent mRNA vaccine-induced antibodies in the blood, which explains why this variant did not cause a widespread surge as previously feared.

However, the study in cell cultures showed this SARS-CoV-2 variant can infect human cells that line the lower lung and engage in virus-host cell membrane fusion more efficiently, two features linked to severe disease symptoms.

The study is published (Jan. 8, 2024) in the journal Cell.

The BA.2.86 variant of omicron is the ancestor of the currently dominating JN.1 and has about 60 more spike protein mutations than the original, or parent, coronavirus, including over 30 more than its close omicron relatives – the early BA.2 variant and the recently dominant XBB.1.5 variant among them. These mutations led scientists to worry that so many changes would make the variant as tough to contain as the initial omicron outbreak in 2021-22.

“But BA.2.86 appears to have increased infectivity of human lung epithelial cells compared to all omicron variants, so that’s a little worrisome. And, consistent with infectivity, it also has increased fusion activity with human lung epithelial cells,” said Liu, also a professor in the Department of Microbial Infection and Immunity. “That raises a potential concern about whether or not this virus is more pathogenic compared to recent omicron variants.”

The published findings coincide with reports from the Centers for Disease Control and Prevention that after a brief increase in BA.2.86 infections, its derived sublineage JN.1 rapidly gained ground in the United States, responsible for an estimated 44% of COVID-19 cases as of Dec. 23, 2023.

Overall, antibodies produced by serum from the bivalent vaccine-dosed health care professionals were more efficient at neutralizing BA.2.86 than they were at neutralizing other omicron variants, including XBB.1.5. In contrast, the three monovalent vaccines and previous XBB.1.5 infection were barely effective in blocking infection by BA.2.86.

Reference: SARS-CoV-2 BA.2.86 is less resistant to vaccine, but may be a problem in the lung; Cell