Half the UK exposed to COVID-19?

Bulletin 2 – Has over half of the UK already been exposed to COVID-19?

Media reporting of a new paper has focussed on a suggestion that over half of the UK may have already been exposed to COVID-19. The paper, published by a team at University of Oxford, does not provide evidence of this. In fact it does not claim to. The paper does demonstrate the current uncertainty over how many people may have been exposed to COVID-19. The authors highlight the need for large-scale testing to reduce that uncertainty.

We support the suggestion that such testing should be carried out. However, we are concerned by the suggestion that much of the population may be immune to the virus. This could undermine key public health messages.

The paper does include combinations of model parameters which assume a low proportion of the population vulnerable to severe disease. This in turn implies a very high prevalence of the virus. We consider these to be the least plausible of the parameter choices illustrated.