What is the significance of the new UK variant of SARS-CoV-2? Perspective from an evolutionary microbiologist

David Kennedy, Penn State

A new variant of SARS-CoV-2 is spreading rapidly in the United Kingdom, with over 1,400 cases since September. SARS-CoV-2, the virus that causes COVID-19, generally accumulates mutations slowly over time, but this new variant had accumulated many mutations quickly.

If this new version of the virus is here to stay, as it appears to be, what does that mean? Will this new version of the virus replace the old one? Will it be easier to catch? And, most important, will the current vaccines still be effective?

This interests me because I am an evolutionary microbiologist who studies the link between the transmission and evolution of infectious diseases. In particular, I spend a lot of time considering the effects of vaccines on pathogen evolution and the effects of pathogen evolution on the impact of vaccines.

What is the new SARS-CoV-2 mutant that has emerged?

The new version of SARS-CoV-2 – named the B.1.1.7 lineage – is spreading in the U.K. and possibly beyond. The differences between the old and new virus include 23 mutations in the virus’s genetic code that have altered four viral proteins.

Eight of these 23 mutations affect the spike protein. This matters because the spike protein enables the virus to enter human cells, and it is a key target of our immune response, both in fighting off the virus during infection and in protecting us from disease following vaccination with the Pfizer and Moderna vaccines.

If the changes to the spike protein help the virus enter human cells more easily, then the virus could be transmitted from person to person more readily.

These mutations may also alter how well the host’s immune system combats the virus, potentially reducing the efficacy of the current vaccines.

What is different about this new version of SARS-CoV-2?

Samples of the new virus isolated from patients suggest that this variant has been increasing in relative frequency over the past three months.

The increase in frequency is concerning, as it suggests – but does not prove – that the B.1.1.7 isolates of SARS-CoV-2 are more transmissible than the original virus. Some have estimated that the new virus may be up to 70% more transmissible than the old virus. While these estimates are consistent with the data, it is entirely too early to make a definitive conclusion.

If this increase in transmissibility is confirmed, it might be due to of the mutations in the spike protein allows it to bind more tightly to the ACE2 receptor, which provides a gateway for the virus to enter human cells.

But it might also be due to any of the other changes to the virus.

Is it more dangerous? If so, why?

If the new version, B.1.1.7, is indeed more transmissible than the old virus, it will be more dangerous in the sense that it will make more people sick.

However, I am not aware of good evidence that there is any difference in severity of disease caused by the new version of this virus compared with the older one. That said, with so few known cases, it may still be too early to say.

Will the Pfizer and Moderna vaccines still be effective against this new strain?

Both the Pfizer and Moderna vaccines work by training our immune systems to recognize a specific version of the viral spike protein. The version of the spike protein used by the vaccines was designed to match that of the old virus, not that of the B.1.1.7 virus. This means that the vaccines might become less effective than expected should this new virus spread widely.

Vaccine-virus mismatch is an ongoing challenge for scientists charged with developing the seasonal flu vaccine. But even with a virus-vaccine mismatch, the flu vaccine reduces the likelihood, and the severity, of disease.

The question is therefore not whether the vaccines will be effective, but rather how effective they will be. The severity of the mismatch matters, but the only way to determine its impact in this case is through scientific study, and to my knowledge, no data on that has yet been collected. In other words, it’s too early to say whether and how this new variant will influence the overall effectiveness of the Pfizer and Moderna vaccines.

Should people still get the new mRNA vaccine?

The appearance of this new B.1.1.7 makes it even more important that people get vaccinated as soon as possible.

If this new version is more transmissible, or if the vaccine is less effective because of a virus-vaccine mismatch, more people will need to be vaccinated to achieve herd immunity and get this disease under control.

Moreover, we now have proof that the spike protein of SARS-CoV-2 can change drastically in a short time, and so it is critical that we get the virus under control to prevent it from evolving further and completely undermining vaccination efforts.The Conversation

David Kennedy, Assistant Professor of Biology, Penn State

This article is republished from The Conversation under a Creative Commons license. Read the original article.


5 thoughts on “What is the significance of the new UK variant of SARS-CoV-2? Perspective from an evolutionary microbiologist”

  1. Everything re mRNA non-“vaccines” is still way too iffy to justify the statement
    “The appearance of this new B.1.1.7 makes it even more important that people get vaccinated as soon as possible”.

    When was “appearance” ever accepted as part of (supposedly) evidence-based medicine ?

    Today mRNA non-“vaccines” only have Emergency Use Authorization. As Dr. Ofitt has clearly left on record “an EUA is an FDA-permission to use something (including stuff that later failed) even though there may not be clear data showing something is safe or effective…So there is a clear learning curve before us “ says Dr. Ofitt

    Low risk ?
    mRNA vaccines insert genetic instructions to induce immune responses without entering the cell’s nucleus. So the chance of its integration into human DNA is “believed” to be very low. Iffy enough ?

    “The science”
    Today “science” has a very limited understanding of Covid-19 and therefore shouldn´t act as if it did. When we are told to abide by “the science” it´s actually only a shred of debatable science as formulated by some scientists inevitably questioned by other scientists…. and reality

    And thus we continue to use the PCR test on a massive scale, despite the fact that its own inventor says it shouldn’t be used for this purpose with tons of false results.

    • Jorge,
      You raise important concerns and we must be vigilant for emerging down-sides to the vaccine. However, the vast majority of ID and public health experts are strongly endorsing early and wide vaccination and feel both vaccines have been appropriately vetted. I got my vaccine and every physician that I know has eagerly signed up for the jab as soon as they could get it.
      I continue to strongly advise my patients and the public to get vaccinated when it becomes available to them.
      Dr P

  2. So are our pals at the CCP retooling their virus to stay one step ahead of vaccine development, and then dropping it “into the wild” to spread? Hopefully the “good guys” can sequence the changes and update the vaccine quckly… and that these “updates” might not require a complete “do over” of the clinical trial process.

  3. Thank you for this article. Good info. Straightforward, not alarmist. Am visiting in Bartlesville, where, despite Washington County being in the red zone, Oklahomans merrily going about their lives largely unmasked, or below-the-nose style. Sheesh!


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