"herd immunity : (epidemiology) The protection given to part of the surviving community against an..."

“herd immunity : (epidemiology) The protection given to part of the surviving community against an epidemic of a contagious disease when a significant number of the population are immunized or develop immunity if they survive from the disease.
Today is recognized by the United Nations as World Health Day to draw attention to global health issues.”

- https://en.wiktionary.org/wiki/herd_immunity#English

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