The new UK SARS-CoV-2 variant and lockdown - causes and consequences.

The new variant of concern (VOC), B.1.1.7, has a distinct set of mutations in nucleotides encoding the spike (S) protein on the surface of SARS-CoV-2. SARS-CoV-2 previously accumulated mutations at a much slower rate, of 1-2 per month; the sudden appearance of a large cluster of mutations was thought to be unusual. We now suspect that VOC may have arisen from immunosuppressed individuals who shed virus for longer periods. Epidemiological analyses estimate VOC to be more infectious; this is of most concern because these estimates were calculated during periods where many regions of the UK were in high social distancing restrictions. Therefore, the previous 'tiered' system implemented in the UK was ineffective at containing VOC. The most likely reason for this is that previous restrictions, no matter how strict, still allowed for gatherings in certain places. VOC also has implications for the national vaccination programme - a higher proportion of people will need to be vaccinated with a more infectious virus. Prolongation of the second dose of vaccines to increase vaccine uptake has understandably caused concern, but is based on sound immunological principles. There is now an urgent need to monitor the effect of new variants on vaccine efficacy - marking a new chapter in the global fight against COVID-19.

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