herd immunity


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herd immunity

[′hərd i‚myü·nəd·ē]
(immunology)
Immunity of a sufficient number of individuals in a population such that infection of one individual will not result in an epidemic.
References in periodicals archive ?
The concept of herd immunity, by which a population develops resistance against a certain disease if a significant proportion of the group is already immune or vaccinated, is no small thing, and is the reason behind the eradication of smallpox and the decline in other communicable diseases.
However, it should be noted that herd immunity is not a permanent state.
No country can achieve herd immunity -- and eventually eradicate preventable infectious diseases -- if it allows parents to opt out of vaccinating their children, as in Greece.
While the current, nearly 10% unimmunized rates add to the likelihood that we are losing complete herd immunity, partial herd immunity is better than no herd immunity.
Killing mosquitoes--a strategy some countries have used to try to curb Zika's reach--could actually hinder herd immunity, letting the next epidemic strike sooner, the team's simulations suggest.
Our study didn't demonstrate crossprotection, type replacement, or herd immunity," said Dr.
Not only does this fact make a mockery out of herd immunity, it draws attention to the fact that people who have been vaccinated can still become infected--thus condemning the arguments of the big-government people.
But now, the whole community benefits from the herd immunity the safe and effective MMR vaccination offers - fewer people get ill and the disease's spread is restricted.
The rationale for mandatory vaccines includes not just disease prevention for individuals but includes the concept of herd immunity (Reiss, 2015).
Likewise, virtually no one, including those who work in healthcare settings, properly understands the complicated multifactor effects of how accurate the antigen selection was for the current flu season, how many people it takes to elicit herd immunity in a region, the likelihood of infectivity from someone who is ill, and how the whole matrix of probabilities interplay to make certain areas resistant or susceptible.
We also find weak evidence of herd immunity effects, whereby hospitalization rates are reduced in adults.
4) Recognizing that the entirety of a population may not be immunized or effectively protected by an immunization, herd immunity is a way to extend protection to the unimmunized and unprotected individuals based on the acquired immunity of a large proportion of the population.