TWiV examines the claim by Brazil’s ANVISA that the Sputnik vaccine contains replication-competent adenovirus, and a role for the furin cleavage site in SARS-CoV-2 spike for efficient reproduction in the respiratory tract, evasion of antiviral IFITM proteins, and transmission in ferrets.

TWiV notes the passing of Mavis Agbandje-McKenna, and reviews data on maximizing fit for cloth and medical procedure masks, SARS-CoV-2 total and subgenomic viral load in hospitalized patients, and effect of changes in spike protein on efficacy in a mouse model of infection.