FILE PHOTO: U.S. Federal Reserve Chairman Jerome Powell speaks to reporters after the Federal Reserve cut interest rates in an emergency move designed to shield the world's largest economy from the impact of the coronavirus, in Washington, U.S., March 3, 2020. REUTERS/Kevin Lamarque/File Photo
FILE PHOTO: U.S. Federal Reserve Chairman Jerome Powell speaks to reporters after the Federal Reserve cut interest rates in an emergency move designed to shield the world's largest economy from the imShow more

US Fed chairman says economic recovery could depend on a Covid-19 vaccine