News about BA.2 omicron subvariant continues to grow as the variant begins to dominate COVID cases in parts of the U.S.
Chicago’s top doctor said BA.2 will likely make up a majority of the city’s cases in the coming days and weeks, a transition health officials are watching closely as metrics begin to see small signs of an increase.
Experts say what happens in the next few weeks in the U.S. could be critical to whether or not the U.S. will follow in Europe’s footsteps.
So what is BA.2, what are the symptoms associated with it, where has it been detected and how contagious is it? Here’s a breakdown.
What is BA.2?
BA.2, also known as “stealth omicron,” is considered a subvariant of omicron.
BA.2 has several key mutations, with the most important of those occurring in the spike protein that studs the outside of the virus. Those mutations are shared with the original omicron, but BA.2 also has additional genetic changes not seen in the initial version.
So far, it has not yet been declared a variant of concern on its own.
“BA.2 is part of omicron,” Dr. Isaac Ghinai, medical director for lab-based surveillance at the Chicago Department of Public Health, said Thursday. “Omicron is a variant of concern, therefore BA.2 is a variant of concern. Same as BA.1 is a variant of concern.”
But that could change.
“People are looking very closely at whether or not BA.2 needs to be classified separately and monitored separately,” Ghinai said. “But even without that it is a variant of concern, it’s being monitored very closely at the local levels, at the state levels and at the national levels.”
How contagious is BA.2?
According to several health experts, BA.2 appears to be more transmissible than omicron.
“There’s four unique mutations in the spike protein that are distinct in BA.2, and different from BA.1. … It seems that these mutations will propel the transmissibility to about a 30% to 50% higher degree of contagiousness than the BA.1 variant,” said Dr. Gregory Huhn, an infectious disease physician and the COVID-19 vaccine coordinator for Cook County Health.
White House chief medical advisor Dr. Anthony Fauci said BA.2 is about 50% to 60% more transmissible than omicron, but it does not appear to be more severe.
“It does have increased transmission capability,” Fauci said Sunday on ABC’s “This Week.” “However, when you look at the cases, they do not appear to be any more severe and they do not appear to evade immune responses either from vaccines or prior infections.”
Northwestern’s Dr. Michael Angarone, an associate professor of medicine in infectious diseases, said the increased transmissibility could be particularly strong in close contacts of those infected, but it’s still too early to tell.
“We’re still trying to figure out why are we seeing this rising number of cases in some of these countries in Europe and that is because there’s something markedly different about the virus,” he said. “So is it more transmissible? Are more people going to become infected from one infected individual? There might be some markers of that.”
What are the symptoms of BA.2?
According to Angarone, the symptoms for BA.2 are similar to those seen in many COVID infections.
“So this is the same virus, so SARS Coronavirus 2, so we’re seeing the same symptoms,” he said.
Huhn noted that while omicron led to more upper respiratory symptoms, it remains too early to tell.
“I don’t know if we, right now, know the particular features that are distinct for BA.2 versus BA.1. I mean, for BA.1, we knew that it was mostly an upper respiratory-type infection rather than the lower respiratory infections that can lead toward pneumonia and further and greater complications,” he said.
For some people, coronavirus causes mild or moderate symptoms that clear up in a couple weeks. For others, it may cause no symptoms at all. For some, the virus can cause more severe illness, including pneumonia and death.
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Read More: What is BA.2 and Why Are You Hearing About the Omicron Subvariant? – NBC Chicago