Neither rain, nor sleet … nor presidential proclamation. President Biden on Thursday mandated COVID-19 vaccines for about 100 million US workers, but the more than 600,000 letter-carriers and administrative staff of the US Postal Service reportedly won’t have to get a shot. A White House official confirmed the exemption to Washington Post postal reporter Jacob Bogage, adding that “we strongly encourage them to comply with these standards” anyhow. It was not immediately clear why postal workers — who serve every community in the United States, often with daily door-to-door deliveries and contact with millions of Americans — would be exempted...