Omicron subvariants are evolving to better evade immunity, as health officials around the world work to prepare for a possible increase in coronavirus infections during the fall and winter.
While there are dozens of subvariants being detected around the world, many of them are likely not to succeed in grabbing a hold over other variants. However, there are three subvariants that many scientists have begun increasingly focusing on in recent weeks: BA.2.75.2, BF.7 (also known as BA.5.2.1.7) and BQ.1.1.
What is BA.2.75.2?
BA.2.75.2 is descended from BA.2.75, a variant which sparked concern among scientists during the summer due to its high number of mutations, but did not succeed in competing with the BA.5 variant in most countries.
Two preprint studies have found that BA.2.75.2 has three additional mutations compared to BA.2.75 and warned that the variant will need to be closely monitored.
The authors of one of the studies wrote that "such rapid and simultaneous emergence of variants with enormous advantages is unprecedented."
Immunologist Yunlong Richard Cao, one of the authors of that study, called BA.2.75.2 and BQ.1.1 the "most antibody-evasive convergent variants tested, far exceeding BA.5 and approaching SARS-CoV-1 level." (SARS-CoV-1 is the original SARS virus which caused an outbreak in the early 2000's)
The study noted that the new variants could escape the majority of neutralizing antibodies, which may make it hard for patients' bodies to neutralize the virus and could lead to more severe symptoms.
The second study found that the neutralization of BA.2.75.2 by antibodies was significantly lower in samples they took in Stockholm than with all other variants they tested, including BA.5. The authors noted that their findings suggest that the variant effectively evades current immunity in the population.
Convergent evolution on steroids v.6I added the 3 lineages that have been designated since Friday.I'm not sure how long we can realistically keep this figure up to date. pic.twitter.com/Sj56i3fKe6
— Marc Johnson (@SolidEvidence) September 25, 2022
Scientists including Shay Fleishon, Marc Johnson, Tom Peacock and Ben Murrell noted in Twitter feeds on the subject that coronavirus subvariants are increasingly showing convergent evolution, meaning that a number of separate lineages evolving separately all appear to be evolving in similar ways.
BF.7 spreads in the US
According to the US Centers for Disease Control (CDC), BF.7 accounted for 3.4% of all cases in the US as of October 1. The week before that, the variant accounted for 2.4% of all cases, and the week before that it accounted for 1.7% of all cases.
CDC spokesperson Jasmine Reed told CBS News that BF.7 could effect the efficacy of Evusheld, a drug used to help immunocompromised Americans who may not be able to get immunity from vaccination. So far there is no indication that BF.7 is more effective at evading vaccines or diagnostic tests.
What is BQ.1.1?
Meanwhile, BQ.1.1, a sublineage of BA.5, is an emerging subvariant that has been showing quick growth in recent weeks, especially in the UK.
BQ.1.1 is showing quite some growth, especially in England where the first sample was submitted 9 days ago and now there are already 28 sequences.I hope there is some sort of biased sampling going on. Otherwise this doesn't look good.@PeacockFlu @kallmemeg @theosanderson pic.twitter.com/cteUne84Cv
— Cornelius Roemer (@CorneliusRoemer) September 21, 2022
According to Cornelius Roemer, a computational biologist from the University of Basel in Switzerland, initial data found using a tool by the Bloom Lab shows that BQ.1.1 is better at escaping antibodies than even BA.2.75.2.
BQ.1.1 was only detected very recently, so more data and analysis will be needed before a more certain idea of the variant's risks can emerge.
Omicron booster shot
HMOs in Israel and in multiple other countries have begun offering a booster shot tailored for the Omicron vaccine recently. In Israel, anyone over the age of 12 can make an appointment at their HMO to get the shot.