The fist stage of the study, conducted by Imperial College, the National Health Service's Royal Free Hospital and hVIVO - experts in viral human challenge models, kicks off in January, and will track an initial group of 90 subjects aged 18-30 who will receive an experimental nasal vaccine before being infected with the disease in a "secure bio-containment suite."

When the government announced the human trial, they said "the aim will be to discover the smallest amount of virus it takes to cause a person to develop Covid-19 infection," adding "This is known as a virus characterisation study and will be backed by £33.6 million of government investment."