An unsubstantiated claim two weeks ago by President Donald Trump — that the “deep state” was slowing approval of a Covid-19 vaccine — has set off an effort by government officials and private industry to ensure the White House doesn’t interfere with a methodical, careful scientific process.Leaders of the U.S. Food and Drug Administration leaders are trying to insulate the agency’s vaccine reviewers from outside political pressure, and drug companies have vowed to make a safe vaccine. Drew Armstrong reports on how government agencies and companies are doing to reassure the public a vaccine will be safe.See omnystudio.com/listener for privacy information.