Highly Mutated COVID Strain Can’t Evade Immunity as Feared

3 min read

Sept. 5, 2023 – The new highly mutated COVID variant BA.2.86 does not have a heightened ability to evade the protection of COVID vaccines or immunity from prior infection, new laboratory tests show.

The BA.2.86 variant grabbed the attention of public health officials in recent weeks due to its quick spread across the globe and a large number of mutations. Having so many mutations increased the chance that it would behave differently than previous versions of the virus, possibly making it more dangerous.

Now, experiments conducted by two teams of U.S. scientists show that antibodies from COVID vaccinations or prior infections can recognize and fight off the BA.2.86 version of the virus, CNN reported, noting that the protection may be “perhaps even better” than antibody responses to other currently circulating strains of the virus.

The new studies showed that people infected within the past 6 months with an XBB-version of the virus had the strongest immune responses to BA.2.86.

“BA.2.86 really doesn't appear to be a huge hit to neutralization after XBB infection. What does this mean? New COVID vaccine (likely coming soon) should provide good protection against infection even against BA.2.86,” former White House COVID coordinator Ashish Jha, MD, MPH, wrote on X, formerly known as Twitter.

The CDC expects the updated COVID vaccine to be available in mid-September. Just like the annual flu shot, the new approach to COVID vaccines is to formulate a new version annually to target strains that are anticipated to be widely circulating. The new COVID vaccine has been optimized to protect against an XBB strain called XBB.1.5.

Last week, the CDC indicated BA.2.86 has been found in four U.S. states, either in people or in wastewater, but it’s still so rare that it’s not even listed as a standalone strain on the CDC’s variant tracker. The current predominant virus strains all remain subvariants of Omicron. Currently, EG.5 accounts for 21.5% of cases, FL.1.5.1 accounts for 14.5% of cases, and several XBB strains account for 8% to 9% each. FL.1.5.1 is a recombinant of two XBB virus strains and may be more worrisome than BA.2.86 because it showed some ability to evade immunity in lab tests, CNN reported.

“If there wasn’t so much hype about BA.2.86, that would actually be the focus of the paper,” Dan Barouch, MD, PhD, told the news outlet, referring to the FL.1.5.1 strain. Barouch is director of one of the labs that conducted the new tests, and he also directs the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Massachusetts.

Since June, there has been an upward climb of serious COVID cases resulting in an increasing number of people being hospitalized with the virus. About 15,000 people were hospitalized during the week ending Aug. 19, which is the most recent week for which data is available from the CDC. Deaths rose from about 500 per week since June to over 600 deaths during the first week of August. Still, the metrics are far lower than during the height of the pandemic, when more than 20,000 people died per week and more than 100,000 weekly hospitalizations were reported.

The CDC in last week’s COVID risk assessment update on BA.2.86 indicated that 97% of people in the U.S. have antibodies from previous infection, vaccination, or both, which “likely” will provide protection against severe cases of COVID-19.