Member-only story
Biology of N501Y, A Novel U.K. Coronavirus Strain, Explained In Detail
[Updated 01/2021] On its (also called VUI-202012/01 or B.1.1.7) evolution, emergence, mutations, virulence, and transmissibility science knows so far.
A new SARS-CoV-2 strain called N501Y has been spreading widely in London and south-east England. “The spread is being driven by the new variant of the virus,” the U.K. Prime Minister, Boris Johnson, said in a press conference. “It appears to spread more easily and may be up to 70% more transmissable than the earlier strain.” This new strain caused about 60% of SARS-CoV-2 infections in London, reported Chris Whitty, England's chief medical officer. As a result, the country was initiating a lockdown yesterday. Many other countries have also restricted travel from the U.K.
Anyways, let’s see what the scientific literature has to say on this newly emerged SARS-CoV-2 strain.
Its evolution
Scientists believe that the N501Y strain evolved in single or a few individuals, rather than mutations accumulating slowly over iterations of virus infections in many different people. In those fighting Covid-19 for an extended duration, SARS-CoV-2 may have mutated at a high rate to keep up with the on-going onslaught by the host immune system.
Indeed, sequencing SARS-CoV-2 genomes revealed a higher mutation rate from patients who did not recover early from Covid-19 and were later treated with remdesivir and convalescent plasma. This may have resulted from a sequence of events that experts in the U.K have proposed, although they cautioned that further verifications are still required:
First, selection from natural immune responses in immune-deficient/suppressed patients will be weak or absent. Second, the selection arising from antibody therapy may be strong due to high antibody concentrations. Third, if antibody therapy is administered after many weeks of chronic infection, the virus population may be unusually large and genetically diverse at the time that antibody-mediated selective pressure is applied, creating suitable circumstances for the rapid fixation of multiple virus genetic changes through direct selection and genetic hitchhiking.
