Collective immunity is described in various ways, for example as:
The proportion of immune persons in the population or particular group,
A certain percentage of vaccinated persons, sufficient to reduce the incidence of the disease or to stop its transmission.
It should also be described as indirect protection. The risk of infection in individuals more susceptible to a particular disease decreases as the number of vaccinated persons in the population increases. However, collective immunity alone does not protect itself against the outbreak of a disease or equate to "classical" biological immunity.
Collective immunity to vaccination will not be replaced
It may therefore seem that unvaccinated children and adults are at some point protected by collective immunity even without their own vaccination. However, these persons:
Remain susceptible to illness if exposed to it in the future,
While reducing collective immunity by not being vaccinated themselves.
Avoiding vaccination with protection from vaccination by others is very short-sighted. An example may be a situation where an unvaccinated child, although in childhood, is not a non-illness against which his parents have not vaccinated, but the disease develops in adulthood. In adulthood, some illnesses may have a much more difficult course or leave behind.
Collective immunity is crucial for, for example, children who can not be vaccinated for any medical reason, whose vaccine fails or where the immune system does not allow vaccination. For such children, the strongest collective immunity is very important.
Targeted vaccination reduces risks
Collective immunity supports not only vaccination according to the established vaccination calendar but also targeted vaccination of selected groups. And the selected group may not necessarily be the most threatened. Proof of this interconnection is an example from Japan. There, when infected with school-aged children, the morbidity and mortality of seniors in the context of flu-like illness decreased.
Maintaining high vaccination is not easy, especially if the incidence of the disease decreases. Why?
In such situations, people tend to underestimate, question or avoid vaccination.
They probably do not fully realize that vaccination, and thus the minimization of the number of people susceptible to the illness, is the downside.
However, this low number needs to be kept at the lowest possible level in the long run by vaccination. Just so it is real to keep even low morbidity.
By vaccinating, and thus by contributing to collective immunity, a person protects himself and his loved ones again.
Source: U lékaře.cz