Dödligt virus från Kina orsakar panik (SARS-CoV-2, COVID-19)

Throughout the ongoing COVID-19 pandemic, the worldwide transmission and replication of
SARS- COV-2, the causative agent of COVID-19 disease, has resulted in the opportunity for
multiple mutations to occur that may alter the virus transmission characteristics, the
effectiveness of vaccines and the severity of disease upon infection. The Omicron variant
(B.1.1.529) was first reported to the WHO by South Africa on 24 November 2021 and was
declared a variant of concern by the WHO on 26 November 2021. The variant was first
detected in the UK on 27 November 2021 and has since been reported in a number of
countries globally where it is frequently associated with rapid increase in cases. Here we
present analyses of UK data showing the earliest signatures of the Omicron variant and
mathematical modelling that uses the UK data to simulate the potential impact of this variant
in the UK. In order to account for the uncertainty in transmission advantage, vaccine escape
and severity at the time of writing, we carry out a sensitivity analysis to assess the impact of
these variant characteristics on future risk

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Despite these caveats, our projections show that Omicron, due to its rapid growth, can generate
levels of infection that could disrupt many services and levels of hospital admissions that will place
a severe burden on the health services. Determining the optimal control policy is highly dependent
on the objective, but several general conclusions can be drawn. First, strong controls enacted
early bring the greatest reduction in infections, hospital admissions and deaths during the first
wave of Omicron. Second, small initial waves lead to larger exit waves, with exit waves of deaths
and hospital admission relatively larger than the exit wave of infection due to changes in the agedistribution of infection. However, such later exit waves, which tend to peak in April 2022, provide the opportunity to learn more about the Omicron variant and to instigate specific controls.