Today, the most infectious Omicron BA.5 subvariant is officially the dominant Covid strain in the US. As far as, BA.5 has tied to its sister subvariant Omicron, BA.4, as both had constantly competed with BA.2.12.1. – who had been pushing cases for the past month or so.
After the original Omicron variant appeared off the coast of the United States late last year and caused the deadliest wave of the pandemic, a succession of Omicron subvariants have come and gone: BA.1.1, BA .2, BA.2.12.1 and now BA.4 and BA.5.
BA.5 was first identified in South Africa on 26 February. Less than a month ago, on June 4, it accounted for only 9.6% of cases in the U.S., while its predecessor BA.2.12.1 sat at the top of 62%. Today, the CDC estimates that the subvariant is responsible for approximately 54% of new cases here. This is double BA.2.12.1, which now accounts for 27% of infections. The increase in BA.5 also leaves the sister subvariant BA.4 in the dust by 16%. It is a faster ascent than that of any other variant throughout the pandemic. And there have been many.
CDC
One of the reasons why BA.5 is so dominant is that it appears to be more transmissible than even BA.2.12.1 (BA.4 has some of the same key protein protein mutations as BA.5, but not has had the same impact). .
“The Omicron BA.5 subvariant is the worst version of the virus we’ve seen,” said Eric Topal, founder and director of the Scripps Research Translational Institute, professor of Molecular Medicine and executive vice president of Scripps. Research, in a subpile post last week. “It takes the immune escape, already broad, to the next level and, based on that, improved transmissibility, far beyond Omicron (BA.1) and other variants of the Omicron family we’ve seen.” .
That is, BA.5 is much better for evading the immunity provided by vaccines and especially for dodging the immunity conferred by the previous infection.
For example, BA.4 and BA.5 recently caused a substantial increase in South Africa that was not affected by the county’s high level of immunity.
According to Nature magazine, those who have “hybrid immunity” from vaccination and a past infection are less able to move away from BA.4 or BA.5 than previous strains. This is because the vaccines we have now are aimed at the earlier protein tip strains. And the new variants have very different mutations.
Although vaccines are less effective, they are and are even more effective than immunization against infection. The blows also help those infected with BA.4 and BA.5 to avoid the most unpleasant effects of the virus.
While the cases have remained fairly static in the United States, the New York Times notes that this may be more a result of the wand than the actual measure. The paper reports that with local and federal cuts to testing services, “laboratory-based PCR testing capacity in July will be only half of what it was in March.” Added to this is the increase in the use of tests at home, the results of which are generally unreported, and nationwide surveillance of the virus is greatly reduced from what it was even six months ago.
Hospitalizations and deaths have also not increased significantly, but in Portugal it took three weeks after the BA.5 peak in cases for deaths to peak.
A more potent ability to reinfect also means that BA.5 has a larger set of potential carriers. While other variants are limited by the protection offered by inoculation, BA.5 may return through populations that assume they are more protected than they actually are.
“BA.4 / 5 caused a substantial wave of cases in South Africa, regardless of their high level of immunity,” Kaitlyn Jetelina noted about two weeks ago. Jetelina tweets and blogs under the nickname Your local epidemiologist.
He goes on to point out that “in South Africa, wave BA.4 / 5 contributed to an excess of deaths, but less than previous waves.”
In Europe, Portugal is the country most affected by the new Omicron subvariants. He experienced a spike in cases on May 16, according to the World Health Organization. Deaths in this country peaked almost exactly three weeks later, on June 6th.
What does this mean for the US?
Our future is more difficult to predict from the experiences of other countries than before. Portugal was hit much harder than the states in the 2000-2001 winter Delta wave and less severe by last winter’s Omicron wave, which hit the US This could be good for us, since the original Omicron is probably more closely related than Delta with BA. 5. Previous Omicron infections can provide more protection. Our winter Omicron wave was also more recent, which helps. But Portugal has a higher reinforcement rate than the US
One thing is certain: this will not be the last variant we will see.
Topol warns that “new versions of the virus … are accelerating and we’re not done yet, not by a long shot.”
In fact, like tropical storms in the Caribbean this summer, there is a line of new variants already underway. And experts say significant mutations, especially in Omicron subvariants, are coming at an increasing rate.
A new strain known as BA.5.1 caused the largest case outbreak ever in Macau last week, prompting local officials to put much of the region under blockade.
BA.5.1 has appeared in the US in small numbers, as well as in the UK and Portugal. The strain has been described as “BA.5’s daughter” and Christine Pagel, a professor and director of the Operational Clinical Research Unit at University College London, wrote in an article last month that “it looks like BA.5 and 5.1 will likely win. become the dominant variants in general “.
Since then, however, BA.2.75 has raised its head. Although not yet found in the United States, the BA.2 subvariant has been detected in England, Germany, and India, where it is said to have been found in 18% of samples. And it’s spreading fast. See the chart below to see the chart of its growth in India.
More, unfortunately, to come.
Here is the latest image of the new BA.2.75 underline (aka: “Centaurus”): an evolutionary leap from BA.2.
It has been detected most frequently in India, showing extremely fast growth up to 18% of recent samples.
It is also spreading rapidly to other countries.🧵 pic.twitter.com/JnkLsU9Lnw
– Mike Honey (@Mike_Honey_) July 2, 2022