Source: United Kingdom – Executive Government & Departments
The New and Emerging Respiratory Virus Threats Advisory Group (NERVTAG) meeting on the SARS-CoV-2 variant under investigation, VUI-202012/01, took place on the 18 December.
Dr Julian Tang, Honorary Associate Professor/Clinical Virologist, University of Leicester, said:
“The spread of this new virus variant could be due to many factors. As we saw with the earlier D614G variant – just higher viral loads in clinical diagnostic swabs or in cell culture may not necessarily translate to a more transmissible virus at the population level.
“A higher genomic growth rate in the samples sequenced, may not necessarily mean higher transmissibility, e.g. if there was a rave of several thousand people where this variant was introduced and infected many people mostly in that rave, this may seem very high compared to a lower background of non-variant virus, e.g. in an otherwise prevailing national lockdown.
“The NERVTAG team appear to be being very careful about such comparisons – and possible ‘founder effects’ that might be misleading – which is good.
“At least two of the mutations in this new variant, N501Y (since at least Apr 2020 in Brazil) and 69-70del (since at least Jan/Feb 2020 in Thailand/Germany) were already circulating globally prior to combining into this new variant.
“This is quite normal for viruses – like influenza – where different viruses may infect the same person, leading to a hybrid virus emerging. This is just one of the ways that natural viral variation arises.
“We are not seeing any increased virulence (clinical severity) or any gross changes in the S (spike protein) that will reduce vaccine effectiveness – so far.
“New viruses will adapt to a new host over time – with decreasing mortality, and possibly increasing transmissibility.
“It makes no sense for the virus to kill its host – rather better for it to replicate to high levels in the host, causing few symptoms – so that the host can stay mobile and appear well (asymptomatic) – to allow it to mingle further with those who are still susceptible – and spread its genes further.
“We are now likely seeing some of this new host adaptation process in SARS-COV-2, but it remains to be seen whether mortality will be different with this variant than with the previous one.”
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