<unk>  is a long-term functional modification of cells in the innate immune system which leads to an altered response to a second unrelated challenge. For example, the BCG vaccine leads to a reduction in childhood mortality caused by unrelated infectious agents. The term "innate immune memory" is sometimes used as a synonym for the term<unk>  which was first coined by the Mihai Netea in 2011. The term<unk> " is relatively new – immunological memory has previously been considered only as a part of adaptive immunity – and refers only to changes in innate immune memory of vertebrates. This type of immunity is thought to be largely mediated by epigenetic modifications. The changes to the innate immune response may last up to several months, in contrast to the classical immunological memory (which may last up to a lifetime), and is usually unspecific because there is no production of specific antibodies/receptors.<unk>  has been suggested to possess a transgenerational effect, for example the children of mothers who had also received vaccination against BCG had a lower mortality rate than children of unvaccinated mothers. The BRACE trial is currently assessing if BCG vaccination can reduce the impact of COVID-19 in healthcare workers. Other vaccines are also thought to induce immune training such as the DTPw vaccine.
Trained immunity
Contact immunity
Herd immunity
Passive immunity
Vaccine shedding
Adoptive immunity
Vaccine resistance
Breakthrough infection