Should we be scared of the Omicron variant?

Why is the government so scared of the Omicron variant? So far, most of the evidence we have for transmissibility and virulence of Omicron is based on very limited data from South Africa, but the UK Health Security Agency (UKHSA) has now published its own preliminary study of the variant — the results of which will presumably have been available to ministers and scientific advisers prior to Wednesday’s decision to enact ‘Plan B’. They appear to show a variant which is more transmissible, more likely to evade vaccines and more likely to reinfect people who have previously had Covid. But there is a very big caveat: they are based on tiny numbers of Omicon cases. As for the severity of Omicron, which evidence from South Africa suggests may be lower than that for previous variants, with far fewer patients requiring oxygen, the UKHSA offers no evidence yet, saying this is still several weeks away.