Governments and private entities are using a small rise in COVID-19 hospitalizations and new viral variants to juice interest in bivalent boosters that only 1 in 6 Americans have taken and to urge a return to routine masking, if not outright mandating new jabs and face coverings. What they aren't providing is robust evidence for the effectiveness of the interventions against infection by a virus that has already provided natural immunity to an estimated 19 in 20 Americans as of November 2022, according to Harvard research published in this month's journal Clinical Infectious Diseases. "If a tiny bump in the...