An analysis of the recently emerged Omicron subvariant of SARS-CoV-2, BA.2.86, shows it has relatively low infectivity and is susceptible to bivalent vaccines, but is able to infect the lungs more thoroughly than earlier Omicron variants.
The BA.2.86 Omicron sub-variant of the COVID-causing virus emerged in the summer of 2023 and caused concern due to the number of new mutations it contained versus the original Omicron variant.
“We found that, surprisingly, despite all those 60 mutations combined together, BA.2.86 is not as immune-evasive as the XBB.1.5 variant, which until recently had been dominating the pandemic for months,” said Shan-Lu Liu, senior author the study and a virology professor in the Department of Veterinary Biosciences at The Ohio State University, in a press statement.
“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… it also has increased fusion activity with human lung epithelial cells.”
Writing in the journal Cell, Liu and colleagues analyzed BA.2.86 next to the earlier lineage XBB Flip variant and assessed its characteristics and susceptibility to available vaccines using cell lines and serum from vaccinated individuals.
They found that although the original three-dose COVID vaccines and the anti-SARS-CoV-2 monoclonal antibody S309 were not able to effectively neutralize the BA.2.86 variant, the more recent bivalent COVID vaccines were largely effective against BA.2.86. This variant also appeared to be less immune evasive than the XBB variants of the virus.
However, BA.2.86 does seem to have a greater ability to infect CaLu-3 human bronchial lung cells than other recent variants, which raises the likelihood of more serious lung involvement in any infection.
“People who have had a COVID-19 infection should remember that omicron variants are less virulent compared to prior variants such as delta, meaning they don’t make most people very sick,” Liu said.
“If you have less severe disease, the antibodies generated by infection are low – almost 10-fold lower than vaccine-induced antibodies. That is why you cannot rely on natural infection alone for immunity.
Liu and team suggest that people should strongly consider getting vaccinated with one of the more recent booster vaccines to help protect against BA.2.86 and similar recent variants such as JN.1.
“While bivalent vaccine can still neutralize BA.2.86, the efficiency is clearly reduced. Therefore, it is important to get the newest booster vaccine” Liu noted.