In June the World Health Organization posted an informational page on COVID-19 and included a definition of herd immunity that has been the standard for infectious diseases for decades, being an “indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection.”
Many high-profile medical organizations also say that herd immunity can be achieved through natural infection. As of December 15, 2020, the Mayo Clinic, for example, says: “Herd immunity can also be reached when a sufficient number of people in the population have recovered from a disease and have developed antibodies against future infection.”
But in October, in an Orwellian move that totally disregards natural infection, the WHO quietly changed its definition of herd immunity to: “a concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached.”
And just in case somebody misunderstands what they mean, they added: “Herd immunity is achieved by protecting people from a virus, not by exposing them to it.”
SOURCES:
WHO June 9, 2020
WHO October 15, 2020
Mayo Clinic December 15, 2020