New coronavirus variant: What we know so far
First identified in the United Kingdom last year, a new variant of the virus that causes COVID-19 has increased concern throughout the world. In this Special Feature, Medical News Today look at what we do — and do not — know about this variant and what health experts have to say.
Recently, global media has been abuzz with news and speculation about a new variant of SARS-CoV-2, the virus responsible for COVID-19.
The variant, which researchers first identified in the U.K., is called B.1.1.7, though as scientists began to express concern about it, initial U.K. government documents dubbed it VUI – 202012/01, standing for “the first variant under investigation in December 2020.”
Later government documents from December designated it as a “variant of concern,” and referred to it as VOC 202012/01.
B.1.1.7 was first spotted in the U.K. in September 2020. It began to draw attention from the scientific community and governmental authorities in early December, when the U.K. health secretary, Matt Hancock, suggested that it was spreading fast and likely contributing to the rising number of SARS-CoV-2 infections in the South of England.
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Now, at the time of this article’s publication, the new variant has been spotted in at least 33 countries.
But why is this variant of so much interest to scientists, public health organizations, and the public at large? In this Special Feature, we review what we know so far about B.1.1.7 and look into the questions that scientists are still trying to answer.
Below, we explore what viral mutations are, how they relate to the development of new viral strains, and whether the new SARS-CoV-2 variant identified in the U.K. is a cause for concern.
Also, MNT have been in touch with Pfizer and the National Institute of Allergy and Infectious Diseases (NIAID) to find out whether the COVID-19 vaccines currently available in the United States and Europe will be effective against B.1.1.7. Learn what they had to tell us.
Article summary:
Why do viruses mutate?
Viruses are prone to mutations. Indeed, all genetic material, including that of humans, can mutate when mistakes occur during replication.
A mutation of a virus occurs when there is a change in its genetic sequence. This creates variation and drives virus evolution.
Mutations lead to changes in the proteins that are encoded in the viral genetic code. These changes can either be advantageous, harmful, or neutral.
How many mutations does it take to produce a new strain of the virus? This is not easy to answer, in part because scientists disagree about the definition of the word “strain.”
In general, if a virus has enough mutations to make its biology significantly different, it may be a considered new strain. This means that it may respond differently to vaccines or treatments, or it may infect a different species or transmit in a different way.
But if the biology of the virus broadly remains the same, despite the mutations, the term “variant” may be more scientifically accurate.
Since the start of the pandemic, there has been much discussion about SARS-CoV-2 mutations and what implications they may have.
SARS-CoV-2, like many other coronaviruses, has an enzyme that proofreads its genetic code during replication, reducing the rate of mutations.
While the novel coronavirus has a relatively stable genome, compared with other types of virus, it does mutate sometimes, and scientists have closely monitored these changes.
One of the most widely talked about mutations has resulted in the D614G variant. This causes a change in the spike protein, which interacts with the ACE2 receptor on human cells to facilitate viral entry.
Specifically, an amino acid in the spike protein at position 614 is changed from aspartic acid to glycine.
Research by Dr. Bette Korber, from the Los Alamos National Laboratory, in New Mexico, and colleagues suggests that this change allows the variant to infect people more easily.
The D614G variant has become the predominant variant of SARS-CoV-2 worldwide, the research shows.
The team’s data indicate that people with the D614G variant of the virus may have higher levels of viral RNA than people with the original variant. But no evidence indicates that this causes more severe COVID-19.
Still, not all scientists agree with this group’s interpretation. Referring to the paper, Dr. Nathan Grubaugh, from the Yale School of Public Health, in New Haven, CT, and colleagues commented that more research is needed to support the idea that this variant is indeed more transmissible.
While researchers continue to study the differences between the D and G variants, the world has turned its focus toward B.1.1.7 and how it may shape the course of the pandemic.
B.1.1.7 and the founder effect
The B.1.1.7 variant has 23 mutations. Six cause no change in the amino acid sequence of the virus. Of the remaining 17 mutations, eight affect the spike protein.
The N501Y change, which involves a switch from asparagine to tyrosine at position 501, is located in the receptor-binding domain of the spike protein. This is a crucial section, as it interacts directly with the ACE2 receptor.
Another mutation in the RNA that encodes the spike protein allows researchers to detect this variant in polymerase chain reaction (PCR) test samples. This is because the mutation lies in one of the targeted areas that many diagnostic PCR tests use.
These tests also use other targets, usually a combination of at least two. Scientists can look for PCR tests that are negative for the spike sequence but positive for the other targets. This would indicate that the person has the B.1.1.7 variant of the SARS-CoV-2 virus.
Researchers from Public Health England used this method to track the spread of the variant in the British population and estimate how its transmissibility compared with those of earlier variants.
But studying how easily a virus transmits from one person to another is technically challenging. Epidemiological data can provide models, and laboratory investigations into the dynamics of infection can uncover more detail. Such studies are ongoing.
Some scientists have called into question whether the B.1.1.7 variant has a higher rate of transmissibility, suggesting that the high numbers of these cases of infection may result from the founder effect.
The founder effect is a term used by scientists who study evolution. It stipulates that a small group of individuals can give rise to a new population.
In the context of viruses, the founder effect could explain how B.1.1.7 has spread so rapidly. Researchers have suggested that superspreading events and a rise in rates of infection throughout England may be the reason for such large numbers of infections with the B.1.1.7 variant.
We spoke to two experts about this.
“While this was initially thought possible when the variant was first identified in September, the evidence has increasingly shown this to be unlikely and has now been largely ruled out,” Prof. Martin Hibberd, a professor of emerging infectious disease at the London School of Hygiene and Tropical Medicine (LSHTM), in the U.K., told us.
Prof. Jonathan Stoye, a group leader at The Francis Crick Institute, in London, whose lab studies virus-host interactions, echoed this sentiment. “Initially I thought this might be the case,” he noted, adding:
“Though it might make some contribution to the initial spread of the new variant, it seems unlikely to explain the greatly increased case incidence, given the simultaneous increase in the proportion of the variant in multiple settings. Rather, it would appear likely that higher levels of virus release, perhaps resulting from the infection of more cells, lead to higher rates of virus transmission.”
– Prof. Jonathan Stoye
Exactly how is B.1.1.7 different?
Many questions about B.1.1.7. remain. How does it compare with preexisting strains, in terms of transmissibility? Is it likely to cause more severe COVID-19? Are children more vulnerable to this variant?
Available research seems to indicate that the new variant has a higher degree of transmissibility.
One study, which has yet to be peer-reviewed but which became available on the preprint server medRxiv on December 26, 2020, used mathematical modeling to estimate the new variant’s transmissibility, compared with that of “preexisting variants of SARS-CoV-2.”
The team of researchers, from the LSHTM, concludes that the B.1.1.7 variant “is 56% more transmissible” than other SARS-CoV-2 variants.
Meanwhile, a report, also in preprint form, from Imperial College London, looks at currently available epidemiological and genetic data and likewise concludes that B.1.1.7 appears to have higher transmissibility than other variants of SARS-CoV-2.
The researchers estimate that B.1.1.7 is 50–75% more transmissible, and they consider the founder effect in their analysis. However, their data speaks in favor of a competitive advantage of this variant over previous variants based on increased transmissibility.
However, Dr. Julian W. Tang, a clinical virologist at the University of Leicester, in the U.K., has cautioned that “It is still difficult to separate out human behavioral versus viral genetic contributions as causes for enhanced transmissibility in all populations,” adding that “In practice, we just have to deal with this.”
Information from Public Health England last updated on December 29, 2020, notes that there is “currently […] no evidence that the variant is more likely to cause severe disease or mortality,” though further investigations are underway.
Prof. Hibberd told MNT that based on existing data from the U.K., the new variant does not appear to lead to more severe cases of COVID-19, compared with other variants or strains of SARS-CoV-2.
“The infection case fatality rate, [which is] based on community population-based estimates of the number of people [with an infection] and the number of deaths observed — estimated from the data in the U.K. — does not seem to have changed significantly, suggesting that the new variant does not cause more severe disease,” he said.
However, he warned that accurate comparative data may be hard to gather, explaining:
“More accurate estimates of the disease severity are being built up over time, based on the observed data directly comparing the new and old variants. But as the old variant becomes rare in the U.K., this will become increasingly difficult. As the variant arrives in other countries, such as the U.S., further data will be [available].”
Impact on public health measures
The rapid spread of infections in the U.K. — largely blamed on the B.1.1.7 variant — throughout December 2020 led first to a local tightening of restrictions, then to the enforcement of strict lockdowns in England and Scotland. Ireland has prolonged its nationwide lockdown, with tighter rules in place.
In the preprint version of the LSHTM study, the researchers warn that given the new variant’s apparently higher transmissibility, “Existing control measures [to contain the spread of the virus] are likely to be less effective, and countries may require stronger proactive interventions to achieve the same level of control.”
In a statement published on December 31, 2020, the World Health Organization (WHO) noted that several countries are already taking what measures they can to stay ahead of the game.
Countries that have observed the spread of new virus variants have “intensified sampling to understand how widely these new variants are circulating,” and scientists have ramped up efforts to understand whether or how new SARS-CoV-2 variants might affect transmission, disease severity, and vaccine effectiveness, according to the statement.
The WHO have also recommended that “Risk communication and community engagement activities [be] scaled up to explain the public health implications of SARS-CoV-2 variants to the public and emphasize the importance of maintaining ongoing preventive measures to reduce transmission.”
One unanswered question about B.1.1.7 concerns the susceptibility of children to the new variant.
In the U.K., schools were largely open during the fall term but have recently closed for most children. Some scientists have suggested that children are more likely to develop an infection with B.1.1.7 than with previous variants of SARS-CoV-2.
However, there is no consensus among the scientific community.
“As children are frequently asymptomatic, it has been difficult to estimate their true population-based infection rates. The initial data seems to suggest that more teenagers are becoming positive, but the data is currently unclear,” Prof. Hibberd explained.
Prof. Stoye shared this view: “Given a more transmissible virus, it seems inevitable that more children will [have an infection with] the new variant and will then [pass this on] to their families. I cannot comment on the impact of infection on the health of individual children; more studies […] will be required to resolve this question.”
COVID-19 vaccines and the new variant
According to Prof. Stoye, there are worries that currently authorized vaccines may not be as effective against new variants of SARS-CoV-2 as they are against preexisting variants that were involved in testing during clinical trials.
“One area of concern relates to the possibility that new variants will show reduced sensitivity to immune responses to the recently introduced vaccines,” Prof. Stoye told MNT. “While it seems unlikely that the current variants will escape, future variants might do so.”
“It will be important to monitor new viruses for neutralization by sera [a blood component] from vaccinated individuals. In the future, it may be necessary to alter the vaccine composition in the way that we do with flu, but hopefully not as often,” he added.
MNT also contacted NIAID, an organization within the National Institutes of Health (NIH) that had collaborated with the biotechnology company Moderna to create a COVID-19 vaccine currently authorized for use in the U.S. and U.K. They explained:
“NIAID scientists have communicated with counterparts at Public Health England, a part of the U.K. government, to closely track their understanding of SARS-CoV-2 VOC 202012/01, also known as the U.K. variant.
At present, NIAID scientists believe that the SARS-CoV-2 vaccines supported by Operation Warp Speed [OWS] will provide protection against SARS-CoV-2 VOC 202012/01, including the OWS-supported Moderna and Pfizer-BioNTech COVID-19 vaccines authorized for emergency use by the U.S. Food and Drug Administration [FDA].”
“As part of a person’s immune response to the vaccine, they produce many antibodies that bind to different locations on the spike protein on the surface of the SARS-CoV-2 virus. Even if a SARS-CoV-2 variant has a few mutations that prevent binding of some antibodies, scientists expect that other antibodies with different binding properties will neutralize the virus,” NIAID also told MNT.
The pharmaceutical corporation Pfizer, whose COVID-19 vaccine — created in collaboration with the biotechnology company BioNTech — has gained authorization in the U.S., U.K., and the European Union, made a similar statement:
“The identification of a new variant of the SARS-CoV-2 virus does not impact the rollout of the Pfizer and BioNTech COVID-19 mRNA Vaccine BNT162b2. Health professionals are advised to continue to follow the official guidance on [the] administration of the vaccine.”
They added that “The companies [Pfizer and BioNTech] are monitoring SARS-CoV-2 sequence changes and working to generate data to evaluate how well serum from people immunized with BNT162b2 may be able to neutralize the new strain.”
Hopeful findings and adaptable technology
In collaboration with scientists at the University of Texas Medical Branch at Galveston, Pfizer recently released a study, currently in preprint form, in which they looked at the N501Y mutation.
Using serum samples from volunteers who had received the Pfizer-BioNTech COVID-19 vaccine in a clinical trial, the researchers analyzed how well the antibodies in the samples could neutralize the SARS-CoV-2 virus.
They found that the sera had “equivalent neutralizing titers,” which means that the same amount of serum was able to neutralize both the original virus and the mutant variant. This indicates that the vaccine will work just as well against the variant.
However, the team only studied the N501Y mutation in isolation, and B.1.1.7 has a number of mutations in its spike protein.
At a press conference on Dec 22, 2020, Dr. Uğur Şahin, the CEO of BioNTech, explained that the company had previously tested their vaccine in combination with a number of SARS-CoV-2 variants and found that it worked well against these. These findings are available in preprint form.
Dr. Şahin added that the company could easily adapt their vaccine platform to combat new variants.
The Pfizer-BioNTech COVID-19 vaccine is based on mRNA technology. This means that the vaccine contains a small amount of the genetic code of SARS-CoV-2 produced in a lab. Once injected as a vaccine, this code instructs our own cells to make the viral spike protein.
Our immune system reacts to this manufactured spike protein and builds up immunity to the SARS-CoV-2 virus. At no point could the vaccine cause COVID-19 because it contains no live pathogens.
Technically, it would not be difficult to change the sequence of the genetic code in the vaccine so that it matches that of the new variant. Dr. Şahin estimates that this would take about 6 weeks.
He noted, however, that health authorities such as the FDA would need to approve any change in the vaccine before it could be administered.
The pharmaceutical company AstraZeneca and the Oxford Vaccine Group did not reply to MNT‘s request for comment regarding their vaccine’s effectiveness against the B.1.1.7 variant.
Another new variant
While much of the news has focused on B.1.1.7, another new variant has emerged. First identified in South Africa, the B.1.351 variant also has the N501Y amino acid change in its spike protein.
It also has two additional mutations in that region, prompting further concerns about how effective vaccination will be. A number of academic experts have told the Science Media Centre, in the U.K., that they believe that existing COVID-19 vaccines can combat this variant, however.
With increased travel restrictions and heightened lockdowns throughout much of the world, how likely is it that these variants will become dominant across wider areas?
“New variants with enhanced growth properties are a concern to everyone. The near-simultaneous appearance of two variants of concern in the U.K. and South Africa suggests that such events can occur in any setting,” Prof. Stoye told MNT. “Short of total separation between different countries, spread will almost inevitably occur.”
“From past experience, it is likely that this new variant will travel widely around the world and is likely to become the dominant strain worldwide,” Prof. Hibberd commented. “This new variant is not likely to be the last and there will, no doubt, be further variants in the coming year or years.”
Both experts stressed the importance of following public health guidelines, such as physical distancing, wearing face coverings, washing the hands frequently and thoroughly, and following all local lockdown rules.
Already last spring, scientists were cautioning the public that the new coronavirus may be here to stay, with waves of infections becoming a seasonal occurrence.
As more variants of SARS-CoV-2 begin to emerge around the world, adherence to these basic public health guidelines is becoming a “new normal,” while national vaccination programs will help gradually build more widespread immunity to the virus.
Dr. Tedros Adhanom Ghebreyesus, director-general of the WHO, has pointed out that difficult experiences such as the ongoing pandemic help bring about much-needed change and improvements:
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