‘Herd immunity’ will be vital to stopping coronavirus

The key phrase we all need to understand is ‘herd immunity’ – which is what happens to a group of people or animals when they develop sufficient antibodies to be resistant to a disease.

The strategy of the British government in minimising the impact of Covid-19 is to allow the virus to pass through the entire population so that we acquire herd immunity, but at a much delayed speed so that those who suffer the most acute symptoms are able to receive the medical support they need, and such that the health service is not overwhelmed and crushed by the sheer number of cases it has to treat at any one time.

The government’s experts – the chief medical officer and the chief scientific advisor – have made two big judgements.

First, as the World Health Organisation on Wednesday in effect conceded, that there is no way now of preventing the virus sweeping across Africa, Asia and the Americas – which in practice means that it will be an ever-present threat to the UK, unless and until a mass vaccine is available for use.