Herd Immunity



According to the World Health Organization, ‘Herd Immunity’ is the indirect protection from an infectious disease that happens when a population is immune (to a virus) either through vaccination or immunity developed through the previous infection. To achieve herd immunity against a disease, a large amount of the population must be either infected or vaccinated. The percentage of the population which needs to be infected or vaccinated varies with the disease. For instance, to achieve herd immunity against measles approximately 95% of the population needs to be immune to the system, for polio it’s about 80%.

For COVID-19, most estimates and studies during the last year projected the threshold at 60-70% of the population for achieving herd immunity. But after more than a year of the COVID-19 pandemic, some data scientists are suspecting whether herd immunity will be achieved any time soon due to several factors like vaccine hesitancy, the emergence of new variants and delayed vaccination of children...read more