TWiV reviews the genetic characterization of a new strain of type 2 oral polio vaccine and its implications for eradication, and how a polymorphism in humans comprising a single amino acid change in an antibody molecule regulates vaccine elicitation of broadly neutralizing antibodies against influenza virus HA.

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.