Herd immunity

Herd immunity, (also called herd effect, community immunity, population immunity, or mass immunity) is a form of indirect protection from infectious disease that can occur with some diseases when a sufficient percentage of a population has become immune to an infection, whether through vaccination or previous infections, thereby reducing the likelihood of infection for individuals who lack immunity.

News

 * 10 Aug 2021, Poolitico.eu, Herd immunity ‘not a possibility’ with Delta variant, Head of Oxford Vaccine Group says vaccination won’t stop spread altogether.
 * 24 May 2021, Politico.eu, Malta says it’s reached coronavirus herd immunity.