Basis of definition | Active Immunity | Passive Immunity |
Definition | Is a type of immunity that results when a person’s own immune system produces antibodies in response to direct contact with an antigen – natural infection or vaccination | Is a type of short-term immunity that is developed by antibodies that are produced externally and then introduced into the body |
Antibody production | Is mediated by antibodies produced by individual’s immune system | Is mediated by the antibodies produced outside the body, when pre-formed antibodies are transferred |
Source | Natural (infection) or Artificial (vaccination) | Maternal antibodies (placenta and breast milk) or artificial (vaccines) |
Pathogen | Pathogen has direct contact with the body | Pathogen does not have direct contact with the body |
Response Time | Does not generate a rapid response – generating an immune response takes time | Generates a rapid response |
Duration of protection | Long-term protection, may be lifelong | Temporary protection, lasts only 2 to 3 days |
Ability to respond to pathogen variants | Can adapt and respond to evolving pathogens | Relies on the transferred antibodies or cells |
Immunological Memory | Generates immunological memory | Does not generate immunological memory |
Examples |
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Effectiveness in immunodeficient hosts | Ineffective | Effective |