TWiV discusses whether or not Omicron should be designated a new serotype of SARS-CoV-2, and the finding that amino acid changes that adapt SARS-CoV-2 to mink or ferret do not increase fitness in the human airway.

TWiV revisits Brazil’s rejection of Sputnik vaccine, examines influenza transmission via the air from the nasal epithelium of ferrets, and a history of accidental releases of polioviruses and their relevance for eradication of poliomyelitis.

On this episode, FDA EUA for Pfizer mRNA vaccine, efficacy of AstraZeneca ChAdOx1 COVID-19 vaccine, and an orally administered drug that blocks SARS-CoV-2 transmission in ferrets.

The TWiVers reveal influenza virus replication in the ferret mammary gland and spread to a nursing infant, and selection of transmissible influenza viruses in the soft palate.