“Herd immunity is a concept used for vaccination, in which a population can be protected from a certain virus as a threshold of vaccination is reached. Herd immunity is achieved by protecting people from a virus, not by exposing them to it. Never in the history of public health has herd immunity been used as a strategy for responding to an outbreak, let alone a pandemic. Allowing a dangerous virus that we don’t fully understand to run free is simply unethical. It’s not an option.” – Director-General Tedros Adhanom Ghebreyesus, World Health Organization press brief, October 12, 2020.

The director-general’s opening remarks come as a response to an announcement made last week of the Great Barrington Declaration, an international proposal written and signed at the American Institute for Economic Research (AIER) in Great Barrington, Massachusetts, on October 4.

The declaration advocates an approach to herd immunity called “focused protection,” where