herd immunity
This term describes a population-level phenomenon rather than an individual medical state. It carries a strong connotation of collective responsibility and public health strategy, often appearing in political and scientific discourse regarding vaccination campaigns.
As an uncountable noun, it refers to a state of being or a threshold of resistance. It does not have a plural form and cannot be counted as individual units; instead, it is measured by the percentage of the population that is immune.
Meanings
The resistance to the spread of a contagious disease within a population that results when a sufficient proportion of individuals have become immune to the disease, typically through vaccination or previous infection.
The government aims to achieve herd immunity to protect those who cannot be vaccinated.