(Reuters) – The U.S. Food and Drug Administration on Tuesday 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% of people who are vaccinated.

More than 100 vaccines are being tested worldwide against the virus, which has claimed over 126,100 lives in the country, according to a Reuters tally.

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 on Tuesday.

Vaccine developers have also been asked to provide data to support use of their vaccines during pregnancy and to show safety and effectiveness in children, the agency said.

Experts have suggested that it could take a minimum of 12 to 18 months to guarantee a vaccine through clinical trials.

(Reporting by Manojna Maddipatla in Bengaluru; Editing by Shinjini Ganguli)