(Reuters) – Here is a summary of some recent studies on COVID-19. They include research that requires further study to confirm results and that has not yet been approved by peer review.
Re-infection, severe outcomes may be more common with BA.5
Compared with the previous variant Omicron BA.2, the currently dominant Omicron BA.5 is associated with higher odds of causing a second infection with SARS-COV-2 regardless of vaccination status, according to a study from Portugal.
From late April to early June, researchers there studied 15,396 adults with the BA.2 variant and 12,306 with BA.5. Vaccines and boosters were equally effective against both subtypes, according to a report published Monday on medRxiv prior to peer review. However, the researchers said that 10% of BA.5 cases re-infected, compared with 5.6% of BA.2 cases, indicating lower protection conferred by previous infection against BA.5 compared to BA.2. Furthermore, vaccines appeared to be less effective in reducing the risk of severe outcomes for BA.5 than for BA.2.
Among those with BA.5, booster vaccination was associated with a 77% and 88% lower risk of hospitalization from COVID-19 and death, respectively, while a higher reduction was found in BA.2, with 93% and 94%, respectively. straight,” the researchers wrote. While “COVID-19 booster vaccination continues to provide significant protection against severe outcomes after BA.5 infection,” they said, their findings provide “evidence of modification of public health measures during BA.5 augmentation.”
Spike viral protein damages heart muscle cells
New research shows that the spiky protein on its surface that the coronavirus uses to break into heart muscle cells also causes a harmful attack by the immune system.
Comparing the effects of SARS-CoV-2, researchers said Wednesday in a presentation at the American Heart Association’s Basic Cardiovascular Sciences Science Sessions 2022, in experiments on mice hearts, that elevated CoV2 proteins and elevated proteins from the coronavirus are different and relatively harmless, and they find that Only the elevated SARS-CoV-2 protein causes heart dysfunction, enlargement and inflammation. Moreover, they found, in infected cardiomyocytes, only SARS-CoV-2 interacted with so-called TLR4 (Toll-like receptor-4) proteins that recognize invaders and induce inflammatory responses. In a deceased patient with COVID-19, researchers found SARS-CoV-2 and TLR4 protein in both cardiomyocytes and other cell types. Both were absent in a biopsy of an intact human heart.
“This means that once the heart is infected with SARS-CoV-2, it will activate the TLR4 signal,” Zhiqiang Lin of the Masonic Medical Research Institute in Utica, New York, said in a statement. “We have provided direct evidence that the spike protein is toxic to cardiomyocytes and have reduced the mechanism behind this because the spike protein directly causes inflammation in cardiomyocytes,” he told Reuters. “More work is being done in my lab to test whether and how the elevated protein kills heart muscle cells.”
Antibody group targeting omicron approaches human trials
Writing Monday in Nature Microbiology, researchers reported that a new group of monoclonal antibodies can prevent and treat omicron infection in monkeys.
The antibodies, called P2G3 and P5C3, recognize specific regions of the barbed protein that SARS-CoV-2 uses to enter cells. “P5C3 alone can prevent all types of SARS-CoV-2 that dominated the epidemic until Omicron BA.2,” said Dr. Didier Trono of the Swiss Institute of Technology in Lausanne. “Then P2G3 comes to the rescue because not only can it neutralize all previous variants of SARS-CoV-2 of concern, but it can also inhibit BA.4 and BA.5,” he said. “P2G3 is effective even against some BA.2 or BA.4/BA.5 escaping mutants (Eli Lilly’s) bebtelovimab, the only clinically approved antibody that still displays activity against the currently dominant BA.4/BA.5 sub variants .”
In lab experiments, mutations that would make SARS-CoV-2 variants resistant to P2G3 did not allow P5C3 to escape, and P5C3 escape mutations still prevented by P2G3, Trono said. “In essence, the two antibodies cover each other, one fills the other’s slips and vice versa.”
Trono, one of the company’s co-founders, said Aerium Therapeutics plans to start testing the kit in humans next month. The company said that if large trials eventually confirm its effectiveness, the P5C3/P2G3 combination will be given by injection every three to six months to people who are immunocompromised and do not have a strong response to COVID-19 vaccines.
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(Reporting by Nancy Lapid; Editing by Bill Bercrout)