An omicron subvariant that has been the dominant strain of COVID-19 in the United States since early July is showing no signs of letting up, causing nearly 90% of the current cases in the country.
According to the weekly “Nowcast” update provided by the Centers for Disease Control and Prevention on Tuesday, the BA.5 COVID subvariant is now responsible for 88.8% of cases in the United States, a slight uptick from last week as it continues its spread.
The BA.5 subvariant has been the dominant strain of COVID-19 in the United States since June 25, and has been responsible for the majority of cases in the U.S. since July 2, according to CDC data.
In the Midwest, the BA.5 subvariant is responsible for 90.1% of cases in an area that includes Illinois, Indiana and Wisconsin, officials say.
The BA.4 subvariant of omicron, which began to circulate around the same time as BA.5, is still responsible for the second-most cases in the U.S. at 5.3%, but it could soon that spot to one of its other sublineages, as the BA.4.6 strain is now responsible for just over 5% of cases, according to CDC estimates.
The continued spread of BA.5 has caused some concern among health officials, as the virus has shown an increased ability to maneuver around immunity gained from previous COVID infections and from vaccines.
Studies have shown that the BA.5 subvariant is three times less sensitive to neutralizing antibodies from existing COVID vaccines than the original omicron variant, which caused a massive surge in cases over the winter.
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While there is no evidence that the variant makes individuals more sick than previous iterations, the increases in cases have led to upticks in hospitalizations and deaths in some locations, according to data from the Illinois Department of Public Health.
That increased transmissibility has caused some concerns, but vaccines have remained effective at preventing serious illness or death from the new variant, according to preliminary studies.
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With omicron’s continued run as the dominant COVID variant, Moderna and Pfizer both intend to release omicron-specific updates to their vaccines as soon as this fall, with the federal government already ordering hundreds of millions of doses of the treatments.
It remains unclear whether the CDC and Food and Drug Administration will recommend omicron-specific boosters in the fall months, with preliminary studies still being performed on the efficacy of the vaccines prior to their release to the public.