January 15, 2021

Weekly line: What the new coronavirus variants mean for vaccines, transmission, and more

Daily Briefing

    News and research regarding emerging new coronavirus variants are moving fast. To help you keep up, here's a 101-level explainer on what the new variants are, where they emerged, and more.

    This explainer covers:

    1. Background on new coronavirus variants
    2. A closer look at variant B.1.1.7
    3. A closer look at variant B.1.351
    4. Other emerging variants
    5. What do the variants mean for Covid-19 tests?
    6. What do the variants mean for Covid-19 treatments?
    7. What do the variants mean for Covid-19 vaccines?
    8. What do the variants mean for Covid-19 response efforts?

    What are these new coronavirus variants, and where did they come from?

    By now, we all know that officials reported the first cases of the novel coronavirus, known as SARS-CoV-2, late last year in Wuhan, China. The virus quickly spread throughout the world, touching every continent and nearly every country.

    Throughout the pandemic, researchers have been testing samples of SARS-CoV-2 to detect whether the novel coronavirus developed any mutations as it spread, which can occur with RNA viruses such as influenza, HIV, the new coronavirus, and more. By May, scientists had identified at least one mutation, known as D614G, but research on whether the mutation made the virus more transmissible was largely inconclusive. However, by September, researchers had catalogued "more than 12,000 mutations in SARS-CoV-2 genomes," Nature's Ewen Callaway reports.

    According to Callaway, many scientists suspected that, if a mutation didn't help the novel coronavirus to spread easier, it likely emerged when the virus was first mutating to jump from animals to humans or from human to human. But scientists didn't think it was likely that the virus would mutate to become more transmissible among humans at this point, because "[a]t a time when nearly everyone on the planet is susceptible, there is likely to be little evolutionary pressure on the virus to spread better, so even potentially beneficial mutations might not flourish," Callaway writes.

    Put another way, William Hanage, an epidemiologist at the Harvard T. H. Chan School of Public Health, told Callaway, "As far as the virus is concerned, every single person that it comes to is a good piece of meat. … There's no selection to be doing it any better."

    The B.1.1.7 variant

    Fast-forward just a few months, however, and officials in the United Kingdom had some troubling news. On Dec. 8, 2020, British officials announced that scientists had discovered a new, potentially far-more-contagious variant of the novel coronavirus in the United Kingdom. U.K. Prime Minister Boris Johnson and England's CMO Chris Whitty said scientists identified the new variant—labeled B 1.1.7—through Public Health England's genomic surveillance. U.K. officials said the variant had about 20 mutations, including several that affect how the virus attaches to and infects cells in the body. Specifically, one of the mutations on B 1.1.7, called N501Y, improves how the spike protein of the virus—which is the part of the virus that infects human cells—attaches to the ACE2 receptor on human cells, meaning the virus is more likely to infect cells successfully.

    Johnson at the time said scientists believed the new variant was more infectious than the original version of the novel coronavirus, and the variant quickly became the dominant type of SARS-CoV-2 spreading throughout the country. According to recent research, B.1.1.7 appears to be about 56% more contagious than the unmutated virus, and researchers have now detected the variant in at least 45 countries, including the United States.

    In the United States, researchers so far have detected B.1.1.7 in a handful of states, but experts say its possible the new variant is more widespread than we know. That's because the United States currently lacks a nationwide system for tracking how coronavirus genomes mutate, with researchers doing genome sequencing on fewer than 3,000 samples a week. Many of the Americans infected with B.1.1.7 haven't traveled recently, which suggests that the variant is already circulating throughout the country via community spread, officials have said.

    The B.1.351 variant

    But B.1.1.7 isn't the only new coronavirus variant on scientists' radar. They've also discovered a new variant in South Africa, called B.1.351, that similarly features the N501Y mutation, as well as an additional mutation called E484K. The E484K mutation occurs on a part of the spike protein that's instrumental in attaching the virus to ACE2 receptors, and it's also been found in a coronavirus variant circulating in Brazil.

    Other emerging variants

    Additionally, on Wednesday, researchers in Ohio reported identifying two additional new variants, including one that appears to be more transmissible than the original version of SARS-CoV-2 and may have originated in the United States. Not much is known about those new variants at this time, but researchers said the variant that may be more transmissible has become the dominant variant circulating in Columbus, Ohio.

    Experts also predict that we could see additional more-contagious new variants of the novel coronavirus as more people gain immunity to the pathogen. Salim Abdool Karim, chair of South Africa's Covid-19 ministerial advisory committee, told the Financial Times, "We're going to see this occur more commonly now than in 2020, as we vaccinate and as more people are infected," because the virus will evolve to help it continue to spread.

    What do the variants mean for coronavirus tests?

    FDA has warned health care providers that the new variants might elude some tests for the novel coronavirus and trigger false-negative results. FDA said that likelihood is low, but it noted three tests— Applied DNA Sciences' Linea test, Mesa Biotech's hand-held Accula test, and Thermo Fisher's TaqPath combo kit—that might produce inaccurate results because of the variants' mutations. In a statement, FDA Commissioner Stephan Hahn said the agency is "working with authorized test developers and reviewing incoming data to ensure that health care providers and clinical staff can quickly and accurately diagnose patients infected with SARS-CoV-2, including those with emerging genetic variants."

    What do the variants mean for Covid-19 treatments?

    But there is some good news: So far, there's no evidence that the new coronavirus variants cause more severe illness or higher mortality than the original version of the virus.

    And although experts have expressed concern that some variants may be more resistant to current treatments for Covid-19, they say there's no evidence indicating as much so far, at least for the currently known variants.

    For instance, Gilead Sciences is testing its Covid-19 treatment remdesivir on both B.1.1.7 and B.1.351, but the company's CEO, Daniel O'Day, on Monday said he believes remdesivir will be effective against them. "Remdesivir works at the source in the cell where the virus replicates, and what we know is, in these new variants, that part of the cell is not changing at all," he said.

    It's more uncertain, however, whether monoclonal antibody treatments for Covid-19 will be effective against variants that have mutations to the portion of the novel coronavirus's spike protein that's targeted by those treatments. As a result, Eli Lilly CEO Dave Ricks on Tuesday told CNBC that he expects the company's antibody drug will be effective against B.1.1.7, but he's not sure whether it will work against B.1.351.

    That's because B.1.351 "has more dramatic mutations to that spike protein, which is the target. Theoretically, it could evade our medicines," Ricks said. He added that Lilly intends to work with FDA to test different versions of the company's antibody drug against the new variants to gauge their effectiveness.

    Separately, George Yancopoulos, Regeneron's research and development chief, on Monday said the company's antibody cocktail drug for Covid-19 could be effective against new coronavirus variants. "We think having a cocktail makes it more likely you'll be able to deal" with the new variants, because "[i]t reduces the likelihood that a single variant can become resistant to both antibodies in the cocktail," he said.

    What do the variants mean for Covid-19 vaccines?

    When it comes to vaccines, a study conducted by Pfizer and scientists from the University of Texas Medical Branch suggests that Pfizer's and BioNTech's coronavirus vaccine is effective in neutralizing the novel coronavirus with the N501Y mutation. That study hasn't yet been peer-reviewed, and it didn't look at the E484K mutation. Pfizer has said it plans to test its vaccine against the E484K mutation in coming weeks.

    According to Medical News Today's Maria Cohut and Yella Hewings-Martin, experts have said Moderna's Covid-19 vaccine should be similarly effective against new variants.

    Some studies have shown that viruses with the E484K mutation are not recognized as well by antibodies as other forms, meaning coronavirus variants with the E484K mutation—such as B.1.351—could potentially bypass immune protection. According to a pre-print paper from researchers at the Fred Hutchinson Cancer Research Center, the location of the E484K mutation is "the site of most concern for viral mutations." Overall, the paper—which tracked how the antibodies in people who had recovered from Covid-19 fared against different variants—found that while there was variability among the samples, some people experienced as much as a 10-fold drop in neutralization against variants with E484K.

    Overall, however, while experts are concerned about the recent mutations, they say it's not likely that they'll render current Covid-19 vaccines and treatments entirely ineffective. According to experts, it would take years—rather than months—for the novel coronavirus to mutate to a point where people's antibodies against the virus or currently authorized vaccines would become ineffective.

    And as CDC recently explained, the United States' currently authorized Covid-19 vaccines "produce a 'polyclonal' response that targets several parts of the spike protein. The virus would likely need to accumulate multiple mutations in the spike protein to evade immunity induced by vaccines or by natural infection."

    Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center, told the New York Times' Apoorva Mandavilli, "No one should worry that there is going to be a single catastrophic mutation that suddenly renders all immunity and antibodies useless." Noting that even the influenza virus needs between five and seven years to gather all the mutations necessary to evade immune recognition entirely, Bloom continued, "It is going to be a process that occurs over the time scale of multiple years and requires the accumulation of multiple viral mutations. It's not going to be like an on-off switch."

    Regardless, vaccine manufacturers say they'll be monitoring whether they need to tweak their vaccines to address the new variants. For instance, BioNTech CEO Ugur Sahin recently said that, if the company's vaccine starts to lose its efficacy because of new variants, his company would be able to adjust its vaccine accordingly—and in an even shorter timeframe. "[T]he beauty of the messenger mRNA technology [that the BioNTech/Pfizer vaccine uses as a platform] is we can directly start to engineer a vaccine that completely mimics this new mutation and we could manufacture a new vaccine within six weeks," he said.

    What do the variants mean for US efforts to address the country's coronavirus epidemic?

    Since the United States doesn't yet possess the robust surveillance program needed to determine how widespread new coronavirus variants actually are in America, public health experts say the country essentially is "flying blind" when it comes to addressing them, the Times' Matt Apuzzo, Selam Gebrekidan, and Mandavilli report. Experts say implementing a national surveillance system in the United States would allow public health officials to warn people in areas affected by the new variants and quickly implement measures meant to stem their spread.

    Without taking action to stop the new variants, and particularly B.1.1.7, they could become the dominant variants circulating in the United States within the next few weeks to a couple months, public health experts say. And while it's currently too soon to tell how the variants will affect the United States' coronavirus epidemic, experts are concerned more-contagious variants could accelerate the country's new case rate.

    That's especially concerning because the United States already is seeing persistently high levels of hospitalizations and deaths tied to the novel coronavirus. Hospitals in some areas of the United States already are overwhelmed by a recent influx of Covid-19 patients, with some having to ration care. If the country sees new cases of the coronavirus and related hospitalizations accelerate even more, the situation could become increasingly dire—similar to what's happened in the United Kingdom, experts fear.

    "Epidemiological models and Britain's experience indicate that, while only a few cases of the variant have been identified in the United States, it will likely become our dominant strain within a few months," Ashish Jha, a general internist and professor of global health at the Harvard T.H. Chan School of Public Health, and Robert Wachter, chair of the department of medicine at the University of California-San Francisco, write in a Washington Post opinion piece. And "a more infectious virus means more cases, which means more hospitalizations and deaths," they add.

    As such, in addition to ramping up surveillance of the new variants in the United States, health officials say Americans need to double down on evidence-backed public health measures that curb the novel coronavirus's spread, such as wearing face masks, social distancing, and frequent hand washing.

    "We don't have any evidence … that the new variant can fundamentally evade masks, social distancing, or the other interventions," Jeff Barrett, director of the Covid-19 genomics initiative at the Wellcome Sanger Institute in the United Kingdom, told BBC News' Helen Briggs. "[W]e just need to apply them more strictly."

    Further, health officials say federal and state health officials must work to get as many Americans vaccinated against Covid-19 as quickly as possible.

    "We are in a race against time," Jennifer Nuzzo, an epidemiologist with the Johns Hopkins Center for Health Security, told the Post's Joel Achenbach and Ben Guarino. "We need to increase our speed in which we act so that we don't allow this virus to spread further and allow [B.1.1.7] to become the dominant one in circulation. The clock is ticking."

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