What is all the fuss about the “mutant” strain of SARS-CoV-2 in England?


A: The variant of concern VOC 202012/01 also known as the B.1.1.7 lineage accumulated many mutations in a short period of time and may spread more quickly than other strains.

Researchers have located three specific mutations that may allow for increased transmission in this variant with continued study expected. It is likely the vaccine will still protect against this variant with further research underway. B.1.1.7 is not believed to cause more severe disease at this time though further research is needed. Variants of concern will continue to present themselves. We need to bulk up our public health tools now to decrease the opportunities for the SARS-CoV-2 virus to change.

First, a biochemistry refresher for whoever needs it. If biochemistry is already your jam, skip to the ***.

Viruses are made of proteins. Proteins are made of amino acids. Amino acids are made from RNA instructions copied from the genetic code of the virus. It is common for errors to take place when genetic code is copied. Most of these changes do not result in different amino acids, but some do. When mutations occur in a sequence that alters the amino acid and subsequently protein building blocks, the function of the virus can change.

Example time. If you are baking a cake and put in a pinch more salt or substitute applesauce for eggs, you generally still get the same cake. If you accidentally swap the baking powder and baking soda amounts or just delete the eggs altogether, you no longer create the same chemical reactions that make the cake…cake. Generally, the “mutant” cake has more trouble entering the body and the next time the recipe is made the changes are fixed. Unlike cake, a “mutant” virus could keep on reproducing itself with the changes, especially if the changes make it easier for the virus to enter host cells.

*** The B.1.1.7 variant has 17 amino acid changes. This significantly exceeds the previous rate of changes seen in the SARS-CoV-2 virus, which has averaged 1-2 changes a month since the beginning of the pandemic. The rapid increase in this variant in England paired with the abnormally high number of mutations are the cause of increased concern and continued investigation.

Emerging evidence suggests the new variant *may* spread quicker than other strains. Of the 17 amino acid changes, 8 occur on the spike protein. The spike protein is the site that binds to human cells allowing the virus to enter. Three specific amino acid changes are currently under study – 69-70del, N501Y, and P681H. In summary, these changes may make it easier for the virus to enter human cells.

While we can see the changes in the virus structure, understanding how the changes influence virus function is much harder. The changes in the spike protein are unlikely to deem existing Covid-19 vaccines ineffective with studies underway to test this hypothesis. The new variant is not believed to cause more severe disease at this time. Further research is needed to understand how changes in the B.1.1.7 variant interact with current treatments and hosts with different characteristics such as age.

The best way to stop dangerous mutations in the SARS-CoV-2 virus is to drastically reduce transmission. We are playing with fire when the virus circulates freely in the community allowing time and hosts for the virus to replicate and evolve. Other variants of equal or greater concern exist, such as a South African variant 501.V2 or a variant not yet detected. The tools to stop concerning variants are blunt and painful instruments – travel restrictions, prolonged social distancing, interruptions to commerce – while research catches up with a changing target. The sooner we vaccinate against the SARS-CoV-2 virus we know, the sooner we can put this tragic and disruptive virus behind us.

The Nerdy Girls will continue to provide updates on this topic as more information becomes available. Until then, stay SMART!

The Nerdy Girls (who couldn’t resist a tribute to the Teenage Mutant Ninja Turtles)

Additional Reading:

Excellent explainer by “Epidummyology”

Summaries from Science and Scientific American

Recent Dear Pandemic post on this specific mutation from December 18th, 2020

Link to original FB post