Herd immunity (also called herd effect, community immunity, population immunity, or social immunity) is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, thereby providing a measure of protection for individuals who are not immune.

In the context of memetics and memes, the same epidemiological mechanisms apply: If an individual host is surrounded by people that don't get easily infected or don't spread toxic memes, the host will indirectly have a smaller chance of getting infected

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