Omicron Variants

More-Contagious BA.5 Omicron Variant Makes Up Nearly 80% of COVID Cases: CDC

NBCUniversal Media, LLC

A COVID subvariant that has shown an ability to better evade a patient’s immunity against the virus is now responsible for nearly 80% of cases reported in the United States this week, according to the Centers for Disease Control and Prevention.

According to the latest “Nowcast’ released by the CDC on Tuesday, the BA.5 omicron subvariant is now estimated to be responsible for 77.9% of COVID cases in the United States.

Another omicron subvariant, known as BA.4, currently makes up 12.8% of cases, representing a slight decline from last week, even as BA.5 continues to gain steam.

The CDC first tracked cases of the BA.5 subvariant back in late April, and its reach has expanded rapidly in the United States, becoming the dominant strain of the virus in early July.

In the span of one month, BA.5 has gone from causing an estimated 29.1% of cases to 77.9% of cases, according to the CDC.

That track basically mirrors what has happened in the Midwest, with a group of six states, including Illinois and Indiana, reporting that 78% of COVID cases are linked to BA.5.

The BA.5 subvariant is causing concerns among physicians for several reasons, most important of which is that it seems to do a better job than previous variants of getting around the immunity caused by vaccinations and by previous COVID infections.

Research indicates that both BA.4 and BA.5 are up to four times more resistant to antibodies from vaccines than BA.2, which was the most dominant strain of COVID in the U.S. for several months over the spring and early summer.

BA.4 and BA.5 cause similar symptoms to previous strains of COVID, including runny nose, sore throat, headache and persistent cough.

The good news is that it does not seem as though the strain causes more severe outcomes for patients who are vaccinated against COVID, although its increased transmissibility could lead to increases in hospitalizations if it starts to impact more vulnerable populations.

In addition to traditional steps like vaccination and masking, some physicians are calling for new booster shots to be formulated to combat the BA.4 and BA.5 subvariants. Pfizer and Moderna have announced that they are changing the formulation of those boosters to combat those subvariants, and new guidance on who is eligible for booster shots could come as soon as this fall, according to officials.

As of Friday, 50 Illinois counties are either at a high or medium-transmission level of COVID, including Cook County and several surrounding suburban communities.

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