<unk>  is the transfer of active humoral immunity of ready-made antibodies.<unk>  can occur naturally, when maternal antibodies are transferred to the fetus through the placenta, and it can also be induced artificially, when high levels of antibodies specific to a pathogen or toxin (obtained from humans, horses, or other animals) are transferred to non-immune persons through blood products that contain antibodies, such as in immunoglobulin therapy or antiserum therapy.<unk>  immunization is used when there is a high risk of infection and insufficient time for the body to develop its own immune response, or to reduce the symptoms of ongoing or immunosuppressive diseases.<unk>  immunization can be provided when people cannot synthesize antibodies, and when they have been exposed to a disease that they do not have immunity against.
Passive immunity
Herd immunity
Trained immunity
Adoptive immunity
Contact immunity
Breakthrough infection
Vaccine resistance
Subclinical infection