New omicron subvariant BA.2 detected in Illinois, could extend current COVID-19 wave
CHICAGO - The new omicron subvariant BA.2 has been detected in Illinois.
The announcement was made Monday by Northwestern Medicine.
The subvariant was detected over the weekend from an individual who was tested for COVID-19 on Jan. 18.
"BA.2 is a specific variant of omicron that carries a number of additional mutations that are thought to make it even more transmissible," said Judd Hultquist, associate director of Northwestern Medicine’s Center for Pathogen Genomics and Microbial Evolution.
"It is unclear if the arrival of this new variant will result in a surge of local cases, but it is an important reminder that we are still in the middle of an ongoing pandemic. Vaccinations, booster shots and the proper use of face masks are still the best ways to protect yourself and your loved ones from this virus," he added.
Data suggests that although the new omicron subvariant is more transmissible, there is no evidence that it is a more severe disease.
However, Dr. Egon Ozer of Northwestern says the possibility of a new surge in infections cannot be ruled out.
WHAT’S KNOWN ABOUT THIS VERSION OF THE VIRUS?
BA.2 has lots of mutations. About 20 of them in the spike protein that studs the outside of the virus are shared with the original omicron. But it also has additional genetic changes not seen in the initial version.
It's unclear how significant those mutations are, especially in a population that has encountered the original omicron, said Dr. Jeremy Luban, a virologist at the University of Massachusetts Medical School.
For now, the original omicron BA.1 and its descendant BA.2 are considered subsets of omicron. But global health leaders could give it its own Greek letter name if it is deemed a globally significant "variant of concern."
Scientists at the UK Health Security Agency found that vaccine effectiveness against symptomatic disease appears similar for BA.1 and BA.2. Looking at all vaccine brands combined, scientists found they were about 70% effective against symptomatic disease from BA.2 two or more weeks after a booster shot.
An initial analysis by scientists in Denmark shows no differences in hospitalizations for BA.2 compared with the original omicron. They are also looking into how well current vaccines work against it. It's also unclear how well treatments will work against it.
Doctors also don’t yet know for sure if someone who’s already had COVID-19 caused by omicron can be sickened again by BA.2. But they’re hopeful, especially that a prior omicron infection might lessen the severity if that happens.
The two versions of omicron have enough in common that it’s possible that infection with the original mutant "will give you cross-protection against BA.2," said Dr. Daniel Kuritzkes, an infectious diseases expert at Brigham and Women’s Hospital in Boston.
Scientists will be conducting tests to see if antibodies from an infection with the original omicron "are able to neutralize BA.2 in the laboratory and then extrapolate from there," he said.
HOW CONCERNED ARE HEALTH AGENCIES?
The World Health Organization classifies omicron overall as a variant of concern, its most serious designation of a coronavirus mutant, but it doesn’t single out BA.2 with a designation of its own. Given its rise in some countries, however, the agency says investigations into its characteristics "should be prioritized."
The UK agency, meanwhile, has designated BA.2 a "variant under investigation," citing the rising numbers found in the U.K. and internationally.
WHY IS IT HARDER TO DETECT?
The original version of omicron had specific genetic features that allowed health officials to rapidly differentiate it from delta using a certain PCR lab test because of what’s known as "S gene target failure."
BA.2 doesn't have this same genetic quirk. So on the test, Long said, it looks like delta.
"It's not that the test doesn't detect it; it's just that it doesn't look like omicron," he said.
WHAT SHOULD YOU DO TO PROTECT YOURSELF?
Doctors advise the same precautions they have all along: Get vaccinated and follow public health guidance about wearing masks, avoiding crowds and staying home when you’re sick.
"The vaccines are still providing good defense against severe disease, hospitalization and death," Long said.
The latest version is another reminder that the pandemic hasn't ended.
"We all wish that it was over," Long said, "but until we get the world vaccinated, we’re going to be at risk of having new variants emerge."
Associated Press contributed to this report.