TWiV returns to the 2012 brouhaha over transmission experiments with avian H5N1 influenza virus, re-examines the claim of SARS-CoV-2 RNA integration into human DNA, and reviews the engineering and testing of a genetically stable version of the attenuated type 2 Sabin poliovirus vaccine.

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.

The TWiV team covers outbreaks of eastern equine encephalitis virus in the US and poliovirus in the Philippines, and explain how a chemokine induced by HIV-1 infection helps release more virus particles from cells.

The TWiV team takes on an experimental plant-based poliovirus vaccine, contradictory findings on the efficacy of Flumist, waning protection conferred by Zostavax, a new adjuvanted subunit zoster vaccine.

The TWiVologists discuss the finding of a second transmissible cancer in Tasmanian devils, and development of new poliovirus strains for the production of inactivated vaccine in the post-eradication era.