TWiV explains genetic changes in nOPV2 strains that paralyzed children, outbreak of raccoon distemper in Toronto, EcoHealth Alliance gets its NIH grant back, and breakage at chromosomal fragile sites caused by the EBNA1 protein of Epstein-Barr virus as a mechanism for carcinogenesis.

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.

Daniel Griffin provides a clinical report on COVID-19, then Amy joins us to discuss the 2020 Chemistry Nobel Prize for gene editing using CRISPR/Cas9, continuing circulation of poliovirus in Afghanistan, inborn errors of interferon in patients with severe COVID-19, and listener questions.

Vincent and Rich discuss fruit fly viruses, one year without polio in Nigeria, and a permissive Marek’s disease viral vaccine that allows transmission of virulent viruses.