What are the differences between active and passive immunity?

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

• Recovery from a bacterial infection
• Vaccination

• Maternal antibodies in newborns
• Administration of immune globulins or monoclonal antibodies

Effectiveness in immunodeficient hosts

Ineffective 

Effective