Herd immunity is when a large number of people are vaccinated against a disease, lowering the chances of others being infected by it.
When a sufficient percentage of a population is vaccinated, it slows the spread of disease.
It is also referred to as community immunity or herd protection.
The decline of disease incidence is greater than the proportion of individuals immunized because vaccination reduces the spread of an infectious agent by reducing the amount and/or duration of pathogen shedding by vaccines, retarding transmission.
The approach requires those exposed to the virus to build natural immunity and stop the human-to-human transmission. This will subsequently halt its spread.
Can it work?
Globally, this strategy has been criticized.
COVID-19 is a new virus to which no one has immunity. More people are susceptible to infection.
The goal seems to have been delaying urgent action to allow an epidemic to infect large numbers of people.
To combat COVID-19, there is an urgent need to implement social distancing and closure policies.