A living WHO guideline on drugs to prevent covid-19 - Lamontagne, Francois; Agoritsas, Thomas; Siemieniuk, Reed; Rochwerg, Bram; Bartoszko, Jessica; Askie, Lisa; Macdonald, Helen; Amin, Wagdy; Bausch, Frederique Jacquerioz; Dourado, Letícia Kawano; Souza, João Paulo Dias de; Stegemann, Miriam (BMJ, 2021)