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This transmission electron microscope image shows the virus that causes SARS-CoV-2 (also known as 2019-nCoV), COVID-19. It emerges from the surface of cells isolated from US patients and cultured in the laboratory.

Source: NIAID-RML

Despite the decline in global Covid-19 infections worldwide, major U.S. health officials have established new, more contagious, and perhaps more deadly variants of the virus in the United States. As it warns of a wave of infections.

Scientists are not surprised by the emergence of new variants, reiterating that currently available vaccines should still be effective against them, although they are a bit less effective than the original “wild” strains. ..However, top US health officials and infectious disease experts have found that these highly contagious mutants, especially the B.1.1.7 strain that emerged in the United Kingdom, Reverse the current downward orbit Having an infectious disease in the United States delays recovery from a pandemic.

“As far as we have, I think we should assume that the next wave of case growth will occur in B.1.1.7, which I think everyone should be more careful about.” Andy Slavitt, senior adviser to White House Covid-19, told MSNBC last week. “It’s nice to see the number of cases decrease, but it can be misleading.”

Why the virus mutates

As the coronavirus spreads, there are huge numbers of copies of itself, and each version is a bit different from the previous one, experts say. SARS-CoV-2, the virus that causes Covid-19, had many opportunities to spread and replicate. The more people are infected, the more likely it is that a problematic mutation will occur.

The three major “variants of concern” that US officials are at stake were first identified in the United Kingdom, South Africa and Brazil.The first B.1.1.7 variant found in the UK Rapid proliferation According to a January study by the US Centers for Disease Control and Prevention, it can occur in the United States and become a major strain in the United States by March.

Through mutations, Dr. Adam Rolling, an infectious disease expert at the University of Michigan at Ann Arbor, simply “is trying to reach the next host and take advantage of itself,” he told the JAMA network. In an interview on February 4th..Like other coronaviruses, SARS-CoV-2 tends to mutate more slowly than other viruses This is because it contains a “calibration” enzyme that corrects some of the changes during replication, such as influenza.

In other cases, “escape mutation” Allow virus adaptation “Evolutionary pressure” is the ability of a virus to spread when it encounters a population that already has some degree of immunity, whether due to previous infection, vaccination, or antibody treatment. Limits, but does not stop it.

“You can think of it as trying a new solution,” Lauring said. “The mutation will make you a better or worse virus, and what you have is the choice. Survival of the fittest for the lack of better terminology.”

Studies show that more interesting viral mutations May come from people Dr. Dennis Burton, chair of immunology and microbiology at the Scripps Research Institute, said immunity because it takes a long time for the body to react to the virus and remove it, and it takes time to understand and mutate us. He said he was incomplete.

“If someone has the virus and they clear it in a few days, you don’t have much chance to mutate,” Burton told CNBC in a telephone interview. “But if someone has the virus like an immunocompromised person and they have the virus for weeks, it will have more chances of mutating.”

Why some are worse than others

According to infectious disease experts, only a few variants are of public health concern. These variants are usually more susceptible to infection, causing more serious illness in infected people and avoiding some protection from vaccines and antibodies.

CDC Director Dr. Rochelle Warrensky I told JAMA on Wednesday The B.1.1.7 variant is believed to be approximately 50% more infectious, and early data indicate that it can be up to 50% more toxic or potentially fatal.

Walensky also suggests that people infected with previous strains of virus may be re-infected with the B.1.351 mutant found in South Africa. From JAMA’s point of view With Dr. Anthony Fauci, Chief Medical Advisor of the White House, and Dr. Henry Walk, Covid Incident Manager at the CDC.

According to the CDC, SARS-CoV-2 is a coronavirus, a large family of viruses named “after the coronary spikes on the surface.” Researchers monitor mutations in these spikes or S proteins because they can help the virus bind to cells and increase the amount of virus released by humans.

Some S proteins are called “receptor binding domains” that act like “spike hands” that grab what is known as the ACE2 receptor in human cells. Dr. Daniel Griffin, responsible for ProHEALTH infections, told CNBC.

Changes in the S protein can be problematic because they are targets of neutralizing antibodies that fight Covid-19 and are produced by natural infections and vaccinations, Griffin said. They can also affect the performance of monoclonal antibody therapies that prevent people from developing serious illnesses.

For example, according to the CDC, the B.1.1.7 variant first identified in the United Kingdom has several different mutations. One of the key mutations, N501Y, is a change in the spike protein that scientists believe makes it easier for the virus to bind to cells.

The same important N501Y mutation occurred separately in the B.1.351 mutant identified in South Africa and the P.1 mutation in Brazil. Both strains have also developed another for mutations in their peplomer known as E484K.

CDC has this mutation Currently identified by some Cases of B.1.1.7 may be resistant to antibody drug therapy, and early studies have shown that some vaccines may be less effective.

“This is what I’m really worried about,” Griffin told CNBC, referring to the E484K mutation.

What does this mean for vaccines

Although the vaccine is still proven to be effective against mutants, there are concerns that the B.1.351 strain may present some challenges.

Large clinical trials from Johnson and Johnson And Novavax Reported that their vaccine was soaked in late January Efficacy when tested in South Africa where the variant first appeared. Novavax said the vaccine With only 49% of the 44 Covid-19 cases in South Africa, J & J said the vaccine was 57% effective in preventing symptomatological Covid-19.

Kate O’Brien, director of vaccination at the World Health Organization, said Thursday that these results were less certain due to the low number of cases in the South African trial group.

“We are still in the early stages of interpreting the evidence, and again, most importantly, we get more information about what is really happening with the disease, O’Brien said at a press conference. That’s it. ” “In general, vaccines are found to retain their efficacy against the disease, albeit at lower levels, in the absence of very widespread mutants.”

Pfizer and moderna

Clinical trials from PfizerBioNTech And Modana Conducted before the mutants emerged, scientists have shown how well blood samples from already vaccinated people respond to laboratory-built viral variants with major mutations. We are conducting laboratory tests to determine.

These studies, which investigate whether serum in the blood neutralizes the virus and prevents replication, Showed poor performance When tested against the B.1.351 variant. “Current vaccination suggests that the mutant may be less effective in preventing infection,” Warensky, Forch, and Walk wrote in their view.

However, your body’s ability to fight the virus, which may help fight the virus, may depend on more than neutralizing antibodies, including T and B cells, which are not measured in early laboratory evaluations. No, Lauring told JAMA.

Fortunately, the Pfizer and Moderna vaccines also showed very high efficacy rates (about 95%) in previous trials. Therefore, there are cushions that allow them to slow down their performance while being considered effective by doctors, experts say. Shot has also been shown to provide protection against severe illnesses that can lead to hospitalization and death.

Both Pfizer and Modana are already Working on booster shots For their vaccine to withstand the B.1.351 strain better.

Find mutations

The B.1.1.7 variant was first identified in the UK in December, but is believed to have emerged at some point in September. Many experts recognize the UK’s ability to perform large-scale genome sequencing to find mutants.

Genome sequencing is an experimental technique that breaks down the genetic code of a virus, and researchers monitor how the virus changes over time and how these changes affect the virus. I understand. To CDC..

According to the latest CDC data, there are currently 1,661 Covid-19 cases recorded in the B.1.1.7 variant, 22 cases in the B.1.351 variant, and 5 cases in the P.1 variant. Authorities acknowledge that the United States has sequenced a small portion of the cases and the spread of the subspecies is probably much wider. However, the federal government has recently sought to increase the number of samples sequenced weekly to detect these and other mutations that may occur in the country.

The CDC is partnering with public health and commercial laboratories to rapidly scale up national genome sequencing. Walensky told JAMA on Wednesday that in January the United States had only sequenced 250 samples a week and has grown “thousands” ever since. “We are not where we need it,” she added.

Dr. Ilhem Messaoudi, director of the University of California, Irvine Virus Research Center, said the process could be time-consuming and labor-intensive, but unless the institute sequenced a specific percentage of all positive Covids, New stocks are overlooked. 19 test results to find new mutations, she said.

“Now we’re trying to catch up,” Mesaudi said in a telephone interview with CNBC. “We’re like’go back and see if this’s there.'”

Mask, social distance

Rapidly prevalent variants control the spread of coronavirus through public health measures such as wearing masks, social distance, and hand hygiene, prevent further mutations, and time for the country to deploy life-saving vaccines. Renews the importance of earning.

However, coronavirus variants are not unique to the United States. If the virus circulates in other parts of the world that are not vaccinated, it can lead to mutations that can threaten vaccines that are widely deployed in other countries, the CDC chief said Wednesday. Warned.

Ultimately, the whole world needs to build immunity to the virus. Otherwise, variants will continue to be a problem, Burton told CNBC.

“Sooner or later, with a big advantage, you’ll have variants everywhere,” Burton said. “This is a global issue, not just a specific country.”

Here’s everything you need to know

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