Dealing with uncertainty about the Omicron variant | David Spiegelhalter and Anthony Masters

Caution is sensible when so much is unknown

The race is on to understand the new variant identified by scientists in South Africa and Botswana, dubbed Omicron (the next Greek letter was nu", but this could have been mistaken for new"). Fears include greater spread, worse disease or reduced effectiveness of treatments and vaccines.

Increased transmission can arise from two factors. First, there is an intrinsic advantage, with a heightened basic reproduction number" R0; in a susceptible population, that is the average number of people each case infects, although after 20 months of pandemic this has become a notional concept. It was around 3 for the original wild-type virus, compared to around 6 for Delta and possibly rather more for Omicron.

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