Biden’s official Twitter account later posted, "The rule is now simple: get vaccinated or wear a mask until you do. The choice is yours." The tweet was quickly picked up by some influential users. Glenn Greenwald, the journalist, retweeted Biden’s comment and posted, "This is not actually a rule." The tweet also raised questions about children who don't have the approval to receive the vaccines. Dana Hull, a Bloomberg reporter, tweeted, "Really hard for parents who have kids under 12 to square this." The Biden administration has been focused on getting more Americans to sign up for COVID-19 vaccines that...