herd immunity: meaning, definition, pronunciation and examples
C1-C2Formal, Academic, Medical, Journalistic
Quick answer
What does “herd immunity” mean?
A form of indirect protection from an infectious disease that occurs when a sufficient percentage of a population becomes immune, thereby reducing the likelihood of infection for individuals who lack immunity.
Audio
Pronunciation
Definition
Meaning and Definition
A form of indirect protection from an infectious disease that occurs when a sufficient percentage of a population becomes immune, thereby reducing the likelihood of infection for individuals who lack immunity.
The concept can be extended metaphorically to describe a state of collective protection in other systems, such as computer networks or financial markets, where widespread adoption of a defense reduces risk for the whole.
Dialectal Variation
British vs American Usage
Differences
No significant lexical differences. British English may more commonly use 'population immunity' as a formal synonym.
Connotations
In both variants, the term gained strong public and political connotations during the COVID-19 pandemic, associated with debates on vaccination strategies and lockdowns.
Frequency
Frequency skyrocketed in both varieties post-2020, moving from a technical term to common public vocabulary.
Grammar
How to Use “herd immunity” in a Sentence
Herd immunity + VERB (is achieved/protects/requires)VERB + herd immunity (to achieve/to rely on/to disrupt)ADJ + herd immunity (sufficient/widespread/natural)Vocabulary
Collocations
Examples
Examples of “herd immunity” in a Sentence
verb
British English
- The strategy aims to herd-immunise the population through a booster campaign.
- We cannot simply herd our way to immunity.
American English
- The strategy aims to herd-immunize the population through a booster campaign.
- We cannot simply herd our way to immunity.
adjective
British English
- The herd-immunity effect was evident once 80% were vaccinated.
- They discussed the herd-immunity threshold.
American English
- The herd-immunity effect was evident once 80% were vaccinated.
- They discussed the herd-immunity threshold.
Usage
Meaning in Context
Business
Rare. Might be used metaphorically: 'Widespread adoption of cybersecurity software creates a kind of herd immunity against attacks.'
Academic
Primary context. Used in epidemiology, public health, virology, and population biology papers.
Everyday
Common in news discussions about vaccines and disease outbreaks.
Technical
Precise use in modelling transmission dynamics, calculating R0 (basic reproduction number), and setting vaccination policy targets.
Vocabulary
Synonyms of “herd immunity”
Strong
Neutral
Weak
Vocabulary
Antonyms of “herd immunity”
Watch out
Common Mistakes When Using “herd immunity”
- Using it to mean individual immunity (e.g., 'I have herd immunity' is incorrect).
- Assuming it is achieved only through vaccination (it can also occur through prior infection, though this is riskier).
- Using it as a verb (e.g., 'to herd immunity' is incorrect).
FAQ
Frequently Asked Questions
No. Herd immunity reduces spread within a population but does not guarantee the pathogen is gone. Elimination (zero cases in a region) and eradication (global zero cases, like smallpox) are far more definitive states.
Yes. If vaccination rates fall below the required threshold (due to vaccine hesitancy, new births, or waning immunity) or if a new, more transmissible variant emerges, herd immunity can be compromised, leading to resurgence.
Generally, no. Relying on natural infection leads to widespread illness, death, and healthcare system overload. Vaccination is a much safer and more controlled method to achieve herd immunity.
No. It significantly reduces risk but does not eliminate it. Vulnerable individuals (e.g., the immunocompromised) within the 'protected herd' can still be infected, especially if the pathogen is introduced by visitors from outside the immune community.
A form of indirect protection from an infectious disease that occurs when a sufficient percentage of a population becomes immune, thereby reducing the likelihood of infection for individuals who lack immunity.
Herd immunity is usually formal, academic, medical, journalistic in register.
Herd immunity: in British English it is pronounced /hɜːd ɪˈmjuːnəti/, and in American English it is pronounced /hɜrd ɪˈmjunəti/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “Reach the herd immunity threshold”
- “A wall of immunity”
Learning
Memory Aids
Mnemonic
Think of a HERD of buffalo. If most are immune to a wolf attack (vaccinated), they form a protective barrier for the few vulnerable calves in the middle. The HERD protects the INDIVIDUAL.
Conceptual Metaphor
COMMUNITY AS A SHIELD / FIREBREAK. Immunity within a population acts as a barrier that stops the 'fire' (pathogen) from reaching vulnerable 'fuel' (susceptible individuals).
Practice
Quiz
What is the PRIMARY mechanism by which herd immunity protects individuals?