Piyush Kumar1*, Anupama2
The Herd immunity is very hot topic during this COVID-19 pandemic era for discussion among scientific community and researchers as well as peoples around the globe. Usually in common term it refers to a herd or group of people or a proportion of population immune to COVID-19 infection among individuals in a population. In other way researcher describe it as the threshold proportion of immune individuals (due to natural immunity or conferred through vaccination) in a population required to decline COVID-19 incidence of infection. Some researchers describe it as a pattern of immunity required to protect a population from invasion of a new infection. In simple words we can say that the chance of infection among susceptible individuals in a population is decreased by the presence and availability of more and more immune individuals which is referred as indirect protection or a herd effect for protection. In this study brief historical, epidemiologic, theoretical, and realistic public health perspectives on this model relevant to COVID-19 were discussed.