What are the features of the new Covid-19/SARS-CoV-2 strain (named lineage B.1.1.7)?
Many news reports are highlighting a novel strain of the virus causing Covid-19 and there seems to be a lot of drama created as flights to and from the UK are being cancelled. What’s lacking from these reports is information about this strain and why should there be so much concern about it.
The following summary is given in a blog maintained by Andrew Rambaut of the ARTIC Network:
“Recently a distinct phylogenetic cluster (named lineage B.1.1.7) was detected within the COG-UK surveillance dataset. This cluster has been growing rapidly over the past 4 weeks and since been observed in other UK locations, indicating further spread.
Several aspects of this cluster are noteworthy for epidemiological and biological reasons and we report preliminary findings below. In summary:
The B.1.1.7 lineage accounts for an increasing proportion of cases in parts of England. The number of B.1.1.7 cases, and the number of regions reporting B.1.1.7 infections, are growing.
B.1.1.7 has an unusually large number of genetic changes, particularly in the spike protein.
Three of these mutations have potential biological effects that have been described previously to varying extents:
- Mutation N501Y is one of six key contact residues within the receptor-binding domain (RBD) and has been identified as increasing binding affinity to human and murine ACE2.
- The spike deletion 69-70del has been described in the context of evasion to the human immune response but has also occurred a number of times in association with other RBD changes.
- Mutation P681H is immediately adjacent to the furin cleavage site, a known location of biological significance.
The rapid growth of this lineage indicates the need for enhanced genomic and epidemiological surveillance worldwide and laboratory investigations of antigenicity and infectivity.”