Even as scientists around the world are closely monitoring the spread of a new, more infectious variant of the novel coronavirus, they have spotted a brand-new, potentially more worrisome mutation—one that could have a far greater impact on the abilities of vaccines to protect people from infection.
About the mutations
In December 2020, U.K. Prime Minister Boris Johnson and England's CMO Chris Whitty said scientists identified a new strain of the new coronavirus—labeled B 1.1.7, which contains multiple mutations from SARS-CoV-2—through Public Health England's genomic surveillance.
Overall, the B 1.1.7 variant appears to be more infectious than the original version of SARS-CoV-2, with some experts estimating the variant is 50% more transmissible. 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.
However, while B 1.1.7 is more transmissible, Johnson said, "There's no evidence that it causes more severe illness or higher mortality." In addition, current evidence suggests the B 1.1.7 variant doesn't have mutations that will have a significant impact on vaccine efficacy, STAT News reports. In fact, a study conducted by Pfizer and scientists from the University of Texas Medical Branch suggests Pfizer's coronavirus vaccine is effective in neutralizing the virus with the N501Y mutation. That study has not yet been peer-reviewed.
But a new variant found in South Africa—which also features the N501Y mutation—features an additional mutation, called E484K. This mutation occurs on a part of the spike protein instrumental in attaching the virus to ACE2 receptors. Studies have found that viruses with this mutation are not recognized as well by antibodies as other forms, meaning the virus could potentially bypass immune protection.
For instance, according to a pre-print paper from researchers at 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.
According to Reuters/U.S. News & World Report, Pfizer plans to test its vaccine against the E484K mutation in coming weeks.
What does this mean for vaccines?
While experts are concerned about the recent mutations of the new coronavirus, they say it's not likely that vaccines will be rendered entirely ineffective as a result.
According to a brief CDC released Sunday, the currently approved 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."
Similarly, Ramon Lorenzo-Redondo, a molecular virologist at Northwestern University's Feinberg School of Medicine, noted, "With one mutation or even three mutations, it's expected the antibodies will still recognize this variant, though they might not recognize it as well as other variants."
Jesse Bloom, an evolutionary virologist at the Fred Hutchinson Cancer Research Center and co-author of the paper on the E484K mutation, agreed the virus would need multiple mutations in specific areas to have a noticeable effect on the efficacy of vaccines. "I'm quite optimistic that even with these mutations, immunity is not going to suddenly fail on us," he said. "It might be gradually eroded, but it's not going to fail on us, at least in the short term."
As other experts explained, the E484K mutation could potentially trick some antibodies focused on a specific part of the virus, but it won't affect antibodies focused on other parts of the virus.
"It is analogous to a key and lock. If that lock changes, maybe the key can't get in," Scott Hensley, an expert in immunology and molecular biology at the University of Pennsylvania, said. "But imagine this not as a single door into a room, but 10 different doors. There will be nine other keys that will be able to get you into that room."
Still reason for concern—and how to prepare
But that doesn't mean there's no reason to be concerned, NBC reports. According to CDC, the potential for the virus to bypass immunity induced by vaccines is the most concerning detail of the recent mutations "because once a large proportion of the population is vaccinated, there will be immune pressure that could favor and accelerate emergence of such variants by selecting for 'escape mutants.'"
That said, CDC added that there's "no evidence that this is occurring, and most experts believe escape mutants are unlikely to emerge because of the nature of the virus."
Rino Rappuoli, a professor of vaccines research at Imperial College and chief scientist at GlaxoSmithKline, added that, while there's no evidence the recent variants of the new coronavirus can bypass vaccine-generated immune response, "we should be prepared that at some point in the future that may happen."
Vineet Menachery, a coronavirus researcher at the University of Texas Medical Branch, said he believes the odds the new coronavirus mutates enough to bypass the currently available vaccines are "unlikely but not impossible," and would take a couple years to happen.
"There's still many steps for the virus to overcome this barrier. We are not even close to that, in my opinion," he said. "The variants are kind of going down that road, but we're not there yet."
If that were to happen, Ugur Sahin, CEO of BioNTech, who developed the new coronaviruss vaccine alongside Pfizer, said 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.
And once a new vaccine was ready, it wouldn't have to go through the extensive regulatory approval process all over again, Jesse Goodman, former FDA chief scientist, said. Rather, it would undergo an approval process similar to the one used to approve influenza vaccines, with a certain amount of initial testing but no full-scale clinical trials.
As of now, however, the key is still getting as many people vaccinated as quickly as possible, according to Stephen Goldstein, an evolutionary virologist at the University of Utah. In fact, it's the transmissibility of the B 1.1.7 variant that makes that perhaps the bigger concern for scientists at present, STAT News reports, since that transmissibility could lead to more hospitalizations and deaths, making it more difficult to corral the virus and increase the threshold of the percentage of people who require protection to reach herd immunity.
"The bottom line hasn't changed: We need to suppress the amount of viral transmission as much as we can," he said. Vaccines are part of that, but so are masks and social distancing, Vox reports. "Outbreaks grow exponentially and you're not going to vaccinate at an exponential rate," he added. "But you can bring outbreaks down to a rate where they are not growing exponentially" (Joseph, STAT News, 1/7; Fox, CNN, 1/6; Belluz/Irfan, Vox, 1/7; Ellyatt, CNBC, 1/6; Erman, Reuters/U.S. News & World Report, 1/7).