Variants of Variants Seen In COVID-Ravaged Brazil
March 24, 2021 – The uncontrolled spread of the most contagious coronavirus variants in Brazil appears to have created even more dangerous versions of the virus that causes COVID-19.
A team of researchers from Fiocruz, a large public health research laboratory run by the Brazilian Ministry of Health, documented the changes. Their findings were recently published in a preprint on Virological.org, before peer review.
The study describes 11 coronavirus sequences from five Brazilian states. Each had telltale changes in the virus receptor, making it one of the known variants. But each also had additional changes in another important region of the virus known as the N-terminal domain (NTD).
The changes were deletions of important antibody binding sites. Many of these were key deletions of a mutation which appeared independently in other circulating variants and which was observed in viral mutations in recovering cancer patients, suggesting that it confers a significant benefit. to the virus.
Since the start of the pandemic, scientists have expected the virus to mutate or change. Viruses can also lose or gain parts of their genetic code. Molecular biology has a term for this: Indel, which means insertion or deletion. Learn more about the coronavirus variants here.
These insertions or deletions are a more abrupt change than a point mutation. When they occur in the spike protein of the virus, they can alter the shape of the coronavirus, allowing it to escape the grip of “lockable” antibodies that adapt to these binding sites.
“Many antibodies are generated for this MTN region. So these mutations are very likely to make the virus even more resistant to neutralization,” study author Felipe Naveca, MD, vice president of the study, told Medscape. research and innovation at Fiocruz Amazonia. .
Modeling by Naveca and his team suggests that the deletions will limit the ability of antibodies to catch these viruses and prevent them from infecting us.
Naveca also says, however, that these variants with indels are still rare. They were observed early and scientists believe they are not yet widespread.
“But the detection serves as a warning and we need to watch for their occurrence. That’s why genomic monitoring is being done,” the researcher said.
Need to “Stop replication”
Brazil is in the midst of another devastating wave of COVID-19 infections, fueled by variants and political inaction. Hospitals are running out of beds and other essential supplies, like ventilators and oxygen, and Brazilian President Jair Bolsonaro has backed down from asking citizens to wear masks and refuses to implement lockdowns, claiming the price to the country’s economy would be too high.
Researchers who were not involved in the study said the findings should put the rest of the world on alert.
John Mellors, MD, chief of infectious diseases at the University of Pittsburgh School of Medicine, said the discovery was “not surprising, but worrying.”
Mellors and his colleagues were part of a team of researchers who documented one of the same changes in a cancer patient who battled the virus for more than 2 months.
Over time, genome sequencing revealed that the patient, who was treated with convalescent plasma and the antiviral drug remdesivir to try to boost his immune response, was the host of at least six different variants of SARS. -CoV-2. The variants had many mutations carried by the variants that appeared in the United Kingdom, South Africa and Brazil.
The N-terminal domain deletions documented in the new pre-print have also been detected in other parts of the world.
A separate study, published earlier this month in the journal Science, found that other deletions also hamper the antibodies. In response to an infection or a vaccine, our bodies make a whole orchestra of y-shaped antibodies that are each designed to cling to a virus in slightly different places. So losing one of these antibody anchor sites on the virus, by itself, is not necessarily alarming. But the more the form of the coronavirus changes and changes, the more our immune defenses lose their collective punch, and ultimately the changes allow the virus to cause reinfection or overcome the protection created by a vaccine.
Other researchers who were not involved in the study said that while the results were interesting and worth watching, it was still too early to know for sure what this particular combination of mutations could mean.
“I’m sure there will be a follow-up document that will profile them to death and like, you know, explain what the exact effects of each of them are, and I’m sure it’s probably just around the corner.” the street, ”said Pavitra Roychoudhury, PhD, instructor in the Department of Laboratory Medicine at the University of Washington in Seattle.
Right now, according to the CDC, which tracks variants, there aren’t any virus variants that cause tests, vaccines or treatments to fail completely.
“The biggest initiative we all need to do is to vaccinate as far as possible to prevent the virus from replicating,” Mellors said. “No replication, no evolution. So if we stop replication and propagation, we’ll be okay, and it’s a huge, huge business across the world to stop it.”
Lack of public health measures
The variables that most influence the evolution of the virus are the number of people infected and the time they spend infected. Scientists agree that in order to slow the evolution of the virus, it is essential to vaccinate quickly and prevent people from circulating, which is not currently happening in Brazil.
“This is very important to ensure the effectiveness of vaccines in the future. They were not designed to cope with this amount of mutations,” said study author Tiago Gräf, who also works with Fiocruz.
“We defend the use of vaccines, and we believe they will continue to protect against serious disease. But the virus is becoming so different from the original that new tests will be needed to understand their effectiveness,” says Graf.
“We show that new variants have appeared and their danger. But the public administration ignores our warnings. The situation we see today is the result,” says Graf.
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