A new Covid-19 vaccine, currently undergoing trials in the US, is likely to get the green light for use in the UK within a matter of weeks. This would make the Janssen vaccine the third to be approved by the MHRA, but the first of its kind in one crucial respect: it only requires one dose.

Janssen, the Belgium-based vaccine arm of American pharmaceutical giant Johnson & Johnson, plans to have results from its large-stage clinical trials ready by the end of January.

Johnson & Johnson said: “If the vaccine is safe and effective, an emergency use authorization application could be submitted to the FDA [Food and Drug Administration] in February.” The UK, which has already secured 30 million doses of the jab, will likely provide authorisation in parallel.