With the BA.2 omicron subvariant continuing to spread across Chicago, Illinois and the U.S., what symptoms should you be watching for?
The “stealth omicron” subvariant has only been the dominant strain of COVID in the United States for less than a month, but the Centers for Disease Control and Prevention now believes that it is responsible for more than 80% of new cases of the virus.
According to the latest updated estimates from the CDC, it is believed that the BA.2 subvariant is responsible for 85.9% of new COVID infections in the United States over the last week. In some parts of the country, that number is even higher, with more than 92% of cases in New York and New Jersey, the CDC says.
In the Midwest, the CDC says that 83.7% of cases are believed to be linked to the subvariant. Less than one month ago, the BA.2 subvariant made up less than 15% of cases, according to the department’s estimates.
That rapid growth in subvariant cases is part of a trend of increasing cases in the state of Illinois. Since the start of April, Illinois has seen its daily case rate climb by 45%, with an average of 1,747 cases per day in the last seven days.
"We are starting to see a steady increase in cases," Dr. Amaal Tokars, acting director for the Illinois Department of Public Health, said during a COVID briefing Tuesday. "Hospitalization in most places continues to be stable. We are seeing some just some bubbling up here and there and that's important to keep an eye on, but overall stable. Death continues to be stable. Again, here in Illinois, we are seeing these rising cases and a context of much lower cases than we had seen in the winter. But still notable and important to point out."
The same could be said for Chicago, which has also seen steady increases in its metrics.
"By far, most of what we are seeing is BA.2," Chicago Department of Public Health Commissioner Dr. Allison Arwady said Thursday. "Not a surprise. It is more contagious than B.1.1, but nothing leading to a major surge."
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.
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."
So with spread continuing to climb, what should you be watching for?
Northwestern's Dr. Michael Angarone, an associate professor of medicine in infectious diseases, said 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.
Dr. Gregory Huhn, an infectious disease physician and the COVID-19 vaccine coordinator for Cook County Health, noted that while omicron led to more upper respiratory symptoms, it remains too early to tell if BA.2 will continue that trend.
"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.
Still, NBC News reported symptoms associated with BA.2 seem to largely mirror a small number of symptoms commonly reported in omicron infections. Those include:
- Runny Nose
Anecdotal reports have suggested that dizziness could be a possible symptom, but they are so far unfounded.
"We will have to wait and see what exactly that means," said Dr. Rachael Lee, an associate professor of infectious disease and a health care epidemiologist at the University of Alabama at Birmingham. Infections in general can cause dizziness if people become dehydrated, she said.
"When we are sick and our body is taking care of the infection, we can get things like fever," Lee said. "If you have fever, in particular, and if you're sweating a lot, you're losing a lot of fluid."
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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.
Most vaccinated people either have no symptoms or exhibit very mild symptoms, according to health officials, and the virus rarely results in hospitalization or death for those individuals.
Still, omicron presented a shift in common symptoms for many.
Dr. Katherine Poehling, an infectious disease specialist and member of the Advisory Committee on Immunization Practices, told NBC News in January that a cough, congestion, runny nose and fatigue appear to be prominent symptoms with the omicron variant.
But unlike the delta variant, many patients were not losing their taste or smell. She noted that these symptoms may only reflect certain populations.
The symptoms COVID infections, according to the CDC, include:
- Fever or chills
- Shortness of breath or difficulty breathing
- Muscle or body aches
- New loss of taste or smell
- Sore throat
- Congestion or runny nose
- Nausea or vomiting