March 29 - April 4 2021
Young people could be more vulnerable to the UK variant
The UK variant of SARS-CoV-2, which appeared at the end of the summer of 2020, spread rapidly across the country between November 2020 and January 2021. It includes numerous mutations and deletions (or losses), notably in the spike (S) surface protein, the protein in contact with the ACE2 cellular receptor which enables entry of the viral particle into the cell. These mutations, in particular the N501Y mutation, increases affinity for the ACE2 receptor, resulting in greater infectivity in animal cell models. British researchers have analyzed the spread of the virus across different regions of England. It appears that the variant is 50% to 100% more contagious.
These researchers analyzed the data from PCR tests and from sequencing in England between the 1st of October 2020 and the 16th of January 2021. The results of some PCR tests allowed them to estimate the number of cases of the UK variant: one of the deletions in the S protein, in position 69-70, makes the S target, one of the 3 parts of the viral genome picked up by the test, undetectable. They were able to conclude that this variant has a selective advantage, making it able to spread 50% to 100% more quickly, depending on the estimation. This advantage could be attributed to a shorter viral cycle, enabling the production of a larger number of viral particles in comparison with the original strain of the virus.
It appears that during the second lockdown in England, during which schools remained open, the proportion of the UK variant increased. And during the third lockdown, during which schools were closed, this proportion decreased. Scientists therefore studied the variant’s transmissibility according to age. They observed that youngsters between 11 and 18 years old had a larger chance of being infected by the UK variant.
In conclusion, it may be that young people are more affected by the UK variant than by other strains. Although the UK variant was detected shortly after its emergence through large-scale sequencing that was rapidly put in place in England, all studies show that this variant is much more contagious than the original strain of the virus. The good news is that drastic sanitary precautions, like those enacted during the third lockdown in England, seem to be effective in slowing down its spread.