The US Food and Drug Administration released guidance on its conditions for approving a vaccine for the coronavirus, saying a vaccine has to prevent or decrease disease severity in at least 50 per cent of people who are vaccinated, Reuters reported.

The Trump administration in May announced a program called “Operation Warp Speed” to speed up the development of Covid-19 therapeutics and vaccines, as the country has none approved for the respiratory illness.

“While the FDA is committed to expediting this work, we will not cut corners in our decisions,” the agency said in a statement.