Reinfection, severe consequences are more common with variant BA.5; A viral protein toxic to heart cells

A medical worker administers a dose of the Comminarty Pfizer-BioNTech coronavirus disease (COVID-19) vaccine to a patient at the vaccination center in Annecys-Saint-Germain, France, Nov. 17, 2021. REUTERS/Stephane Mahe/File Photo /File photo

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July 28 (Reuters) – Below is a summary of the latest research on COVID-19. They include studies that require further research to confirm their findings and have not yet been peer-reviewed.

Reinfections, severe consequences may be more with BA.5

An independent study from Portugal has shown that the current predominant Omicron BA.5 vaccination status is more likely to cause a second SARS-COV-2 infection compared to the previous Omicron BA.2 subvariant.

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Between late April and early June, researchers studied 15,396 adults infected with the BA.2 variant and 12,306 with BA.5. Vaccines and boosters were equally effective against both sublines, according to a report published Monday in medRxiv. However, 10% of BA.5 cases were reinfections, compared to 5.6% of BA.2 cases, indicating a reduced defense against previous infection in BA.5 versus BA.2, the researchers said. In addition, the vaccines appeared to be less effective in reducing the risk of severe outcomes for BA.5 compared to BA.2.

“Among those infected with BA.5, booster vaccination was associated with a 77% and 88% reduction in the risk of COVID-19 hospitalization and death, respectively, while a higher risk reduction of 93% and 94% was found for BA.2 cases, respectively,” the researchers wrote. “Covid-19 booster vaccination still offers significant protection against severe sequelae following BA.5 infection,” they said, adding that their findings provide “evidence for adjusting public health interventions during BA.5 outbreaks.”

The viral protein damages heart muscle cells

A surface protein that the coronavirus uses to enter heart muscle cells triggers a harmful attack by the immune system, according to new research.

The SARS-CoV-2 protein interacts with other proteins in cardiac myocytes to cause inflammation, researchers reported Wednesday at the American Heart Association’s 2022 Basic Cardiovascular Sciences Scientific Sessions. In experiments with the hearts of mice, overexpressing SARS-CoV-2 proteins and proteins from another relatively harmless coronavirus, the researchers found that only the SARS-CoV-2 protein caused heart dysfunction, enlargement and inflammation. In addition, they found that in infected heart muscle cells, only SARS-CoV-2 spikes interacted with TLR4 proteins (Toll-like receptor-4), which recognize invaders and trigger inflammatory responses. In a patient who died of COVID-19 inflammation, researchers found SARS-CoV-2 protein and TLR4 protein in heart muscle cells and other cell types. Both were absent in a heart biopsy from a healthy individual.

“Once the heart is infected with SARS-CoV-2, it activates TLR4 signaling,” 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 heart muscle cells and narrowed down the underlying mechanism because the protein directly inflames heart muscle cells,” he told Reuters. “More work is going on in my lab to test if and how the spike protein kills heart muscle cells.”

Omicron-targeted antibody combination nears human trial

A new monoclonal antibody combination prevents and treats Omicron infections in monkeys, researchers reported Monday in the journal Nature Microbiology.

The antibodies, called P2G3 and P5C3, recognize specific regions of the spike protein that the SARS-CoV-2 virus uses to enter cells. “P5C3 alone can block all SARS-CoV-2 variants that dominate the pandemic up to Omicron BA.2,” said Dr. Didier Trona of the Swiss Institute of Technology in Lausanne. “Then P2G3 comes to the rescue because it can not only neutralize all the previous SARS-CoV-2 variants of concern, but also block BA.4 and BA.5,” he said. “P2G3 is the only clinically approved antibody able to evade bebtelovimab, even against some BA.2 or BA.4/BA.5 mutants (Eli Lilly’s (LLY.N)), currently showing dominant activity against BA.4. /BA. 5 subvariants”.

In laboratory experiments, mutations that made SARS-CoV-2 variants resistant to P2G3 did not allow them to escape P5C3, while P5C3 escape mutants were still blocked by P2G3, Trono said. “Essentially, the two antibodies cover each other, and one fills in the other’s deficiencies, and vice versa.”

Aerium Therapeutics plans to begin testing the combination in humans next month, said Trono, one of the company’s co-founders. If larger 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 reaction to the COVID-19 vaccine, the company said.

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Reporting by Nancy Lapid; Edited by Bill Berkrot

Our standards: Thomson Reuters Trust Principles.


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