New Covid-19 Strains: What Scientists Know About Coronavirus Variants

In South Africa, meanwhile, doctors and researchers are studying a second rise in Covid-19 cases, and are studying another new variant and what role it plays in the increasing tide of cases. The variant, known as B.1.351, has been identified in samples dating from October. It has not yet been detected in the US

Here’s what we know so far about the new variants and the genetic mutations that characterize them, as well as their potential impact on public health.

What is a viral variant?

Viral variants are new versions of a virus that arise as a result of small changes in its genetic code. In the course of the pandemic, there were different variants. Those who appeared to be able to distribute more efficiently appeared more and more, while others circulated. “It’s just like natural selection, like evolution,” said Bettie Steinberg, a virologist and provost at Feinstein Institutes for Medical Research, of Northwell Health.

Why the concern about these specific variants?

Some doctors are concerned that the new variant of the coronavirus could increase the spread of Covid-19, which could put additional strain on hospitals and nursing homes if the cases are near their historic peak.

Preliminary data indicate that the new variants are no more likely to cause serious diseases than the more well-known forms of the coronavirus. But even if their virulence is not greater, the increasing transmissibility of the variants can cause more misery and death by increasing the number of cases of Covid-19.

Researchers from the London School of Hygiene and Tropical Medicine have combined behavioral and epidemiological data on the spread of disease with mathematical models to determine whether the UK variant is more transmissible than previously identified.

They found that the new variant is more transferable than previous variants.

UK contact detection data show that patients infected with the new variant infected more people than those infected with previous variants. Data also suggested that the virus load, or the amount of virus in the body, was higher among people infected with the new variant. The higher the viral load for individuals, the more contagious they are.

Is it possible that the rapid spread of the new variant is not the result of increased contagion, but instead the poor adherence to social distance and other measures that try to curb the infection?

Scientists do not think so, at least in the UK. As proof, prof. Neil Ferguson, an epidemiologist at Imperial College London and a member of a scientific panel advising the British government on threats to respiratory viruses, has been pointing out epidemiological data since November. showing that cases of the new British variant were exploding in south-east London as cases of coronavirus fell in other parts of the country. The whole country was in the lock during this period.

The situation may be different in South Africa, where researchers have said that human behavior may play a key role in the increase in cases. Millions of South Africans have traveled extensively in recent weeks, and tens of thousands have gathered in restaurants and bars and on beaches during the holiday season.

What gave rise to the new variants?

Like other viral pathogens, the coronavirus spreads by infecting cells and then reproducing, creating copies of itself that are spread throughout the body and then shed, potentially infecting other people.

The reproduction process involves copying the genetic code of the virus, which contains the instructions for building up successive generations of virus particles, or virions. But the code is not always reproduced faithfully; sometimes the copying errors yield errors that researchers have compared to typographic errors. This is what gives rise to new viral variants, such as those that have recently emerged.

Some viruses have genetic DNA codes, the same molecule that carries the genetic information in human cells. Other viruses, including the coronavirus, are based on a related molecule known as RNA. RNA viruses have no molecular proofreader, a protein that looks for errors and corrects them, so that they “accumulate typing errors faster”, said dr. Steinberg said.

What about the mutations seen in the new variants?

The new variant that has emerged in the UK has about two dozen separate mutations, some of which are related to the prominent effects that cover the outer surface of the coronavirus. It is the so-called vein protein that helps the virus invade cells by binding to their outer membranes and then breaking them.

In theory, a mutated form of the vein protein may increase the ability of a virus to attach to cells, thus enabling the infection to increase efficiency. Previous research has shown that one mutation in the British variant can make the virus more contagious, said Dr. Ravindra Gupta, a virologist from Cambridge University who conducted the studies, said.

The South African variant has more than 20 mutations, including several that affect the ear protein. Some are in the most important places where antibodies prevent the virus from entering the cells, according to scientists, which means that it could possibly help the virus evade someone’s natural immune response.

The British and South African variants share a vein protein mutation that enables the bait to bind more tightly to cell membranes, according to research.

Do existing vaccines work against new variants?

Although there is still no final word on whether the existing vaccine was made by Pfizer Inc.

and BioNTech SE and those of Moderna Inc.

granted immunity to the new variants, scientists expressed confidence that they do so.

The mutations ‘raise some questions about the effectiveness of the vaccine, but it is important to note that the vaccines elicit a broad immune response … which targets various parts of the peak protein,’ says Dr. . Richard Lessells, an infectious disease specialist at the University of KwaZulu. -Natal in Durban, South Africa, and a member of the team that discovered the South African variant.

Pfizer and Moderna have performed laboratory tests of their vaccines against several versions of the coronavirus and, according to the drug manufacturers, have found that the vaccines are effective against all of them. The companies said they were conducting experiments to determine whether antibodies generated by vaccinated people were effective against the British and South African variants.

The Centers for Disease Control and Prevention calls on people who are eligible for vaccination to get the shots. “Based on studies with other viruses that contain similar mutations, the CDC believes there will be little or no impact on immunity to natural infection or vaccination,” the agency said in a statement Tuesday.

How will scientists know for sure whether these new variants will spread more easily?

Scientists have said that they have studied some of the individual mutations of the new variants, but that it will be important to look at what happens when they appear together – as in the new variants. That research involves experiments in cells and in animals to test whether the new variants attach and penetrate cells more effectively; or repeat them more easily; and, most importantly, whether it spreads more easily.

Animal studies with an earlier coronavirus variant have convinced some scientists that the particular mutations made it more contagious, said Dr. William Hanage, a biologist from the Harvard TH Chan School of Public Health who specializes in infectious diseases, said. The version of the virus also has a mutated ear protein.

What can be done to stay safe against the new variants?

Proponents of infectious diseases and public health officials say it is important to adhere to known strategies to avoid contamination, including social distance, masking and hand washing, as well as to avoid exposure to other people in indoor environments, especially where ventilation is poor. Extra caution will be required during indoor meetings if experiments confirm that the new variant is contaminated.

—Joanna Sugden contributed to this article.

Write to Daniela Hernandez at [email protected] and Sarah Toy at [email protected]