The hits just keep coming. The U.S. has seen more than 24 million COVID-19 cases and 406,000 deaths from the disease in the last 10 months. Right when we’re starting to see the light at the end of the tunnel when it comes to the COVID-19 pandemic—thanks to promising vaccines—we get hit with a setback: the first major variant of the SARS-CoV-2 virus that seems to behave significantly differently than we’ve come to expect. This variant, dubbed B.1.1.7, was first found in the U.K. in September. By December, it accounted for 60% of all coronavirus cases identified in London, resulting in widespread travel restrictions and new lockdowns in the U.K. and Ireland. This coronavirus variant is now present in at least 60 countries and several U.S. states.
So where does this leave us right now? And most critically, is there any way to better protect ourselves from these concerning new coronavirus variants? For some insight, SELF checked in with Emma Hodcroft, Ph.D., a molecular epidemiologist at the University of Basel in Switzerland, and Joseph Osmundson, Ph.D., a clinical assistant professor of biology at New York University.
First: What exactly is a SARS-CoV-2 variant?
The virus that causes COVID-19, SARS-CoV-2, has about 30,000 letters in its genome (the total genetic material of the virus). When it replicates, some of these letters change by mistake. “Any single letter change is a variant,” explains Dr. Osmundson. Most of these changes won’t make a difference in how the virus behaves. “Some mutations may lead to an inactive virus,” Dr. Osmundson says. “Very rare variants may act measurably different from the original strain.” The original strain is typically referred to as the “wild type” virus. Sometimes, a variant that behaves differently can provide the virus with an advantage over its wild type counterpart, like being able to spread more easily.
While a virus with even a single mutation is technically a new variant, many variants contain multiple mutations. These are identified by sequencing the entire genome of the virus and looking for places that don’t match up with the wild type virus. A letter may be different or missing altogether. Viruses that have the same collection of mutations are then given names to distinguish them from the wild type. “Other viruses that are sampled and that have the same mutations are considered part of that ‘variant,’” Dr. Hodcroft explains.
What variants are out there right now, and why are they concerning?
We’re currently looking at an alphabet soup of different variants in SARS-CoV-2. There are two garnering the most attention. One troubling variant was first found in the U.K. and is known as B.1.1.7, and sometimes as 501Y.V1 (the latter designation refers to one of the key mutations it contains). The B.1.1.7 variant contains 23 mutations that differentiate it from the wild type virus. Another variant that’s causing concern, 501Y.V2, recently emerged in South Africa and has at least 21 mutations that have changed from the wild type. (Unlike B.1.1.7, it hasn’t yet been detected in the U.S.)
Both of these coronavirus variants have mutations in the SARS-CoV-2 spike protein, which is a key coronavirus protein. The spike protein is what enables the virus to get into a person’s cells and replicate, causing infection. The B.1.1.7 variant has received the lion’s share of attention to date because it appears to increase viral transmission compared to the wild type. Dr. Hodcroft notes that this variant (and 501Y.V2, to a lesser extent) has been “associated with worrying rises in cases.” Dr. Osmundson agrees with this concern. “Epidemiological data from different populations show an increase in the transmission of 50% to 70%,” he says. “This has yet to be confirmed in animal models and across broader epidemiological data. It’s strong preliminary data.” A Centre for Mathematical Modelling of Infectious Diseases study released from the U.K. (but not yet peer-reviewed) suggests that the B.1.1.7 variant is “56% more transmissible” than pre-existing SARS-CoV-2 viruses in the country, but Dr. Osmundson notes we don’t know yet exactly why the virus is easier to spread. “Tighter binding to host cells? Higher viral titers in the nose or throat leading to more shedding? Faster or better viral replication? We have no data here whatsoever.”
A small silver lining is that the B.1.1.7 variant does not seem to be more deadly than others circulating. However, if the increased transmission leads to additional infections, we still may end up with more deaths from COVID-19. “The concern with more transmission is that if more people get the virus, even if the proportion who are hospitalized or die stay the same, a fraction of a big number is a big number,” notes Dr. Hodcroft.
Will COVID-19 vaccines still work against these variants?
The authorized vaccines from Pfizer/BioNtech and Moderna target that important spike protein using mRNA technology. Since the B.1.1.7 and 501Y.V2 variants involve mutations to the spike protein, some experts are worried that the variants may be able to prevent immunity, either from natural infection or from immunization. The most concerning spike protein mutation in the B.1.1.7 variant from the U.K. is dubbed N501Y, while the 501Y.V2 variant first found in South Africa has a spike protein mutation labeled E484K. In a not-yet-published study, researchers found that in 21 of 44 people who got coronavirus in the first wave of infection in South Africa, their antibodies didn’t recognize 501Y.V2. Though this isn’t definitive proof that this variant can escape immunity, it bears watching and additional testing.
Pfizer has already tested a number of spike protein mutations and recently reported that their vaccine seemed to still be effective against the most worrisome spike protein mutation in B.1.1.7. They also tested 15 other spike protein mutations, and “none of them have really had any significant impact” on the vaccine’s effectiveness, a Pfizer vaccine scientist told Reuters. (Moderna is currently carrying out similar testing with their vaccine). Notably, Pfizer hasn’t yet tested the spike protein mutation in 501Y.V2, and there is some preliminary data (not yet peer-reviewed) suggesting that mutation may be a better candidate for escaping immunity. But Dr. Hodcroft cautions: “It is hard to predict how lab results translate to real life, as the systems are much more complex.”
The next two vaccines that seem likely to get authorized—one from Johnson & Johnson, the other from Oxford/AstraZeneca—work differently from the Pfizer/BioNTech and Moderna vaccines. But they both rely on the viral spike protein, meaning mutations to that protein could theoretically affect these vaccines’ effectiveness similarly.
Should we worry about other variants?
While the B.1.1.7 and 501Y.V2 variants may be the most scrutinized currently, we’ve seen other variants come and go—a pattern likely to persist as the pandemic continues. Dr. Hodcroft worked on an analysis of a variant in Spain, 20A.EU1, that spread across Europe in summer 2020. In that case, the increased spread of the variant seemed to be unrelated to any particular mutation in the virus that made it more transmissible. Instead, researchers chalked it up to human behavior, including travel. Dr. Hodcroft notes, “This shows that human behavior is incredibly important. [20A.EU1] is the most prevalent variant in Europe right now, and it didn’t need higher transmission to get there.”
Another variant experts are examining is one from Brazil, B.1.1.28. This variant contains the same E484K mutation as the variant from South Africa and appears to have caused COVID-19 reinfection in a health care worker in Brazil. “Home-grown” variants appear to have originated in California and Ohio as well and may be linked to increased transmission, but those variants need additional testing and characterization for us to know for sure.
What can we do now that more concerning variants are circulating?
While these variants are concerning, the best way to slow their transmission is the same as what public health experts have advised since the early days of the pandemic. “Wear a mask, wash your hands, keep your distance, avoid crowds, and be aware of aerosol transmission indoors,” Dr. Hodcroft says. “Limit your contacts. The virus depends on us to meet each other in order to transmit; we make that opportunity happen. So we can take that opportunity away through our behavior.”
When it comes to masks specifically, President Biden’s COVID-19 response plan includes asking the public to wear masks for 100 days, along with mask mandates on federal grounds and interstate transportation. General support for mask wearing from the president may further signal their importance. But in light of these new variants, some experts are recommending that the general public—not only people like health care workers—begin to wear medical-grade masks. It’s not clear exactly how more people will be able to access medical-grade face coverings like surgical masks and N95s, since most guidance calls for us to reserve them for health care workers. Biden is planning on using the Defense Production Act to increase the nation’s mask supply, among other goals—you can read more about that here.
Distribution and uptake of the authorized vaccines are also essential. “Get the vaccine out as fast, as widely, but as well as possible,” Dr. Osmundson says. “We should not be skipping steps (e.g. only doing one shot), as weak immunity may drive viral escape from the vaccine.” Receiving the vaccine when you can plays an important part in breaking those chains of transmission and reducing the number of available hosts the virus can spread to—and available opportunities for mutation.
Vaccines will hopefully become more widely available, and distribution more organized, in the coming months. Increasing vaccine manufacturing is a key part of Biden’s coronavirus plan, and results from new vaccines, like the Johnson & Johnson candidate, are expected within weeks. The Johnson & Johnson vaccine requires just a single vaccine dose for protection instead of two, unlike Pfizer/BioNTech and Moderna, though the company is reportedly behind on production.
On top of all of this, Dr. Hodcroft cautions that additional protective policy changes may be necessary in locations where these new variants show up, especially B.1.1.7. “Countries should have a plan,” she says. “What will they do if the variant is detected? What levels of cases are concerning? What actions will happen if those levels are reached? Being prepared to take early and strong action can have a big impact on how the pandemic progresses, so having a plan before you need it is key.”
Ultimately, it’s critical that we stop coronavirus transmission however possible. Not only will this protect us from current circulating variants, but it will also reduce the threat of future variants that may result in a worst-case scenario: the evolution of a variant that is both more transmissible and causes more severe disease, and that may also be able to evade immunity from prior infection or vaccination. The best way to avoid this is to stop giving the virus more hosts—meaning, people—where it can evolve. Although it’s encouraging that none of the variants that have been tested are definitely able to readily escape immunity, we can’t assume that will be the case with every variant that may arise.
Related:
- Should We All Be Wearing Better Masks to Protect Against COVID-19 Variants?
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