Throughout much of the pandemic, there has been a constant shift in which COVID-19 variants are most dominant in the U.S. at any given time.
However, for the past five weeks, federal data shows that there has been little to no growth in the varying proportions of COVID-19 variants in the country.
For more than nine months, the omicron variant and its sub-variants have been dominant in the US. But now health experts say it’s unclear why the growth of the omicron strains appears to have stalled, or why no other significant variants have emerged to challenge its dominance.
“Unlike previous variants, BA.5 appears to have more stamina. A mix of higher transmissibility, declining immunity, and relaxed restrictions likely contribute to this variant’s ability to find more hosts to infect,” said John Brownstein, Ph. .D. , an epidemiologist at Boston Children’s Hospital and an ABC News contributor.
BA.5 is currently estimated to be responsible for about 88.6% of new COVID-19 infections — a proportion that has plateaued in the past five weeks, according to updated data from the Centers for Disease Control and Prevention.
BA.4 currently accounts for an estimated 2.8% of new cases in the US, and a recently identified subvariant, BA.4.6, accounts for an estimated 8.4% of new cases — a slight increase from last week when the sub variant was good for 7.6. % new cases.
Combined, the BA.4 and BA.5 subvariants account for nearly 100% of new cases in the US, according to CDC data.
According to the World Health Organization, the BA.4 and BA.5 subvariants appear to have a transmission advantage over the parent strain of omicron, which is why scientists have been closely monitoring the increase in reported cases. At this point, BA.5 does not appear to have an increase in severity.
The slowdown in the growth pattern of the omicron strain leaves many unanswered questions about whether there will be a viral resurgence in the fall and winter.
“We still have open questions about what this means for a fall wave and the possibilities for a new variant to displace it,” Brownstein said.
The stagnation of growth with the ommicron variants comes as the US appears to be experiencing a parallel plateau of new COVID-19 infections. The nation reported consistent declines throughout late summer, but in recent weeks, that number has hovered around 84,000 new cases per day, according to the CDC.
As previously reported, dozens of states have moved to closed public testing sites, with more at-home COVID-19 testing now available. Most Americans don’t report their results to officials, which is why experts suggest infection totals are likely significantly understated.
Just over 400,000 tests are reported every day, which is the lowest number of confirmed tests since the start of the pandemic.
While new cases are still declining in parts of the West, in areas of the Northeast, Midwest and even parts of the South, cases have remained at high levels or are showing signs of rising again.
Hospital admission levels also appear to be stabilizing nationally. According to CDC data, about 5,100 virus-positive Americans enter the hospital every day, down about 3.7% from the past week.
Death rates also remain persistently high, with hundreds of Americans still losing their lives to the virus every day. According to the CDC, the average number of daily COVID-19-related deaths remains above 400 reported deaths per day.
Thousands are still losing their lives every week, and the US has reported more than 2,800 deaths in the past seven days alone — still one of the highest weekly totals in months.
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