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So far, how the United States has defeated a variant of the coronavirus

On December 29, Colorado National Guard became the first known case in the United States of a new variant of the coronavirus infectious agent.

The news was uneasy. This variant, called B.1.1.7, made a noise in Britain, began to surge in Europe, and threatened to do the same in the United States. Scientists didn’t know that yet, but other mutants were also harvested nationwide. They contained variants that devastated South Africa. Brazil And it seemed to be able to circumvent the immune system, and others are homemade In California, With Oregon New York..

This variant of melange would not have arrived at the worst of times. The country was at the beginning of a post-holiday surge in incidents that would diminish all previous waves.And the distribution of a powerful vaccine made by Moderna and Pfizer-BioNTech We’re screwed By chaos and misunderstanding. Scientists have warned that variants, especially B.1.1.7, could lead to a fourth wave, disrupting the already tense healthcare system.

It didn’t happen. B.1.1.7 has become the leading version of the virus in the United States and currently accounts for almost three-quarters of all cases. But surge experts were afraid to end up with just a blip in most of the country. The national total of new daily cases began to decline in April and is now down more than 85 percent from the horrific highs in January.

Kristian Andersen, a virologist at Scripps Research in La Jolla, California, said:

Dr. Andersen and other virus watchers have identified variants as a potential source of problems in the coming months. In particular, it has hit Brazil and is growing rapidly in 17 states in the United States. However, they have also acquired shares in the past few months to better understand how the country has avoided the threat of variants.

Experts point out a combination of factors (masks, social distances, other restrictions, and perhaps seasonal decline in infection) that tens of millions of Americans spent decisive time getting vaccinated. I am. They also admit a significant amount of serendipity because B.1.1.7, unlike some of its competitors, is powerless against vaccines.

“Honestly, I think we were lucky,” said Nathan Gourbo, an epidemiologist at Yale University. “We are rescued by the vaccine.”

After the advent of B.1.1.7 at the end of December, a new variant with a nasty combination of mutations was revealed. Scientists were worried about how competition between subspecies would take place.

In January, California researchers discovered a mutant with 10 mutations. Growing more generally there And it was drifting to another state. Laboratory experiments have suggested that the mutant can evade antibody treatments that worked well against previous forms of the virus, and is probably more contagious.

In the months that followed, the United States dramatically improved its surveillance of how variants mutate. Last week, over 28,800 viral genomes (nearly 10% of all positive test cases) were uploaded to an international online database called GISAID. The clearer image allowed scientists to see how the mutants compete.

California variants turned out to be weak competitors, and their numbers dropped sharply in February and March. It’s still prevalent in parts of Northern California, but it has virtually disappeared from the southern part of the state and hasn’t found a foothold elsewhere in the country. By April 24, B.1.1.7 surged to 66%, accounting for only 3.2% of all virus samples tested in the country.

“B.1.1.7 participated in the knockout, which is like a’bye-bye, California variant’,” said Dr. Andersen.

On the other side of the country, researchers reported in February that a variant called B.1.526 spread rapidly in New York and appeared to be a formidable enemy of B.1.1.7. By February, each of these variants had grown to about 35 percent of the samples collected by Dr. Grubaugh’s lab in Connecticut. However, B.1.1.7 came to the top.

In fact, B.1.1.7 seems to have an advantage over almost all variants identified so far. At a parliamentary hearing on Tuesday, Dr. Rochelle P. Warrensky, director of the Centers for Disease Control and Prevention, said B.1.1.7 accounted for 72 percent of cases in the country.

Emma Hodcroft, an epidemiologist at the University of Bern, said:

The variants identified in California and New York turned out to be moderately more contagious than older versions of the virus, and many of the first successes may have been lucky. The overall boom in the case of last fall amplified what would otherwise not have been detected.

It’s unclear why B.1.1.7 is better than other products. “Is it the largest of all varieties? Angela Rasmussen, a virologist at the University of Saskatchewan’s vaccine and infectious disease tissue, said:” What does the combination of all these mutations do? Further research is needed to understand what it is. ”Some answers may come from California, where researchers stage a direct competition in the laboratory, B.1.1.7 and others. Inject the mice with a cocktail of 6 variants of.

Dr. Charles Chiu, a virologist at the University of California, San Francisco, who was the first scientist to discover a variant of California, said:

In Michigan, one of the few states where a surge in cases was predicted this spring, B.1.1.7 found a hook for young people returning to school and doing contact sports.

Emily Martin, an epidemiologist at the University of Michigan, said:

But in the rest of the country, people were naturally more cautious when faced with the horrific victims of the virus after vacation. B.1.1.7 is believed to be about 60% more contagious than previous forms of the virus, but there is no difference in its mode of spread. In most states, there were at least partial restrictions on the mandatory indoor diet and masks.

“B.1.1.7 is more contagious, but you can’t jump over the mask,” said Dr. Hodcroft. “So we can still stop its spread.”

However, other experts are still dissatisfied with the virus appearing to be unexpected.

Sarah Coby, an evolutionary biologist at the University of Chicago, said: Respiratory viruses can go through a seasonal cycle, but it is not clear why the coronavirus cycle reduced it in the middle of winter. “It makes me feel probably more ignorant,” she said.

It is also puzzling that variants that have hit other countries have not yet become widespread in the United States. B.1.351 rapidly dominated South Africa and several other African countries at the end of last was First reported It occurred in the United States on January 28, but still accounts for only 1 percent of cases. This may be due to the inability to stay ahead of the rapidly prevailing B.1.1.7.

William Hanage, an epidemiologist at Harvard School of Public Health, said:

Brazil’s devastating variant, the P.1, made a slow start in the United States, but is now Estimated To account for more than 10 percent of national cases.

“I think it’s only a matter of time before the P.1 variant becomes one of the most prevalent in the United States,” warned Dr. André Ricardo Ribas Freitas, a medical epidemiologist at Faculdade São Leopoldo Mandic in Brazil.

Still, the University of Utah’s evolutionary biologist Nels Elde said that the events of the last four months are worth worrying about different varieties rather than focusing on behaviors that can suppress them all. He said he had questioned whether or not.

“We’re splitting hair between several mutations here and there, we’ve lost some perspective,” he said. “It’s a catnip for a curious mind.”

The United States also has a sufficient supply of powerful vaccines that make varieties an academic concern rather than a cause of concern for the average person. The vaccine may be slightly less effective against the mutants identified in South Africa and Brazil, but it prevents serious illness from all known mutants.

It is not impossible for the situation to get worse.about 35 percent of U.S. people are fully vaccinated, And vaccine protection may diminish by winter. No one knows how variants emerging in other parts of the world behave here, such as those that have become prominent in India and are distributed at low levels in the United States. And where the virus is widespread, more variants will inevitably occur, Dr. Cobey warned: “There are still many evolutions to occur.”

So far, how the United States has defeated a variant of the coronavirus

Source link So far, how the United States has defeated a variant of the coronavirus

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