The definition of Herd Immunity has changed over this past year (2020-2021) on the World Health Organization’s website. Apparently, due to COVID.
Interestingly though, Herd Immunity is not simply a COVID thing. It is something that is relevant for all infectious diseases. Nonetheless, COVID has resulted in changing the definition of Herd Immunity from:
BEFORE
Herd immunity is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection. This means that even people who haven’t been infected, or in whom an infection hasn’t triggered an immune response, they are protected because people around them who are immune can act as a buffer between them and an infected person. The threshold for establishing herd immunity for COVID-19 is not yet clear.
AFTER
‘Herd immunity’ also known as population immunity, is a concept used for vaccination, in which a population can be protected from a certain virus if a threshold of vaccination is reached.
Herd immunity is achieved by protecting people from a virus not by exposing them to it. Read the Director generals 12 October media briefing speech for more detail.
Keep in mind that when you read this their definition may have changed again. The challenge and blessing of an online world is that you can change things online easily. You can keep the same date, put it back, or move it forward, depending on your needs. So, just because you read something online one way doesn’t mean that is what it said originally.
It has now changed again, after checking today, to the following
‘Herd immunity’, also known as ‘population immunity’, is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection. WHO supports achieving ‘herd immunity’ through vaccination, not by allowing a disease to spread through any segment of the population, as this would result in unnecessary cases and deaths.