The two main types of immunity are active and passive.
Active Immunity
Active immunity develops when your body produces its own antibodies in response to an antigen (a substance that triggers an immune response). This happens naturally after infection or through vaccination.
- Naturally acquired active immunity: This occurs when you get sick with an infection, and your immune system learns to recognize and fight off that specific pathogen. For example, recovering from chickenpox results in active immunity against that virus.
- Artificially acquired active immunity: This is achieved through vaccination. Vaccines introduce a weakened or inactive form of a pathogen, stimulating your immune system to create antibodies without causing the full-blown disease. This provides long-lasting protection.
The CDC (https://www.cdc.gov/vaccines/basics/immunity-types.html) and Children's Hospital of Philadelphia (https://www.chop.edu/vaccine-education-center/human-immune-system/types-immunity) both confirm this classification.
Passive Immunity
Passive immunity involves receiving antibodies from an external source, rather than producing them yourself. This provides immediate, but temporary protection.
- Naturally acquired passive immunity: This occurs when a mother passes antibodies to her baby through the placenta during pregnancy (IgG antibodies) or through breast milk (IgA antibodies).
- Artificially acquired passive immunity: This is achieved through injections of antibodies, like antivenom for snake bites, or immunoglobulin therapy for certain infections. This provides immediate protection but is short-lived as the body doesn't produce its own antibodies.
As noted in several sources, including a July 30, 2024, article (reference not hyperlinked but mentioned in prompt), antibodies are disease-specific. For example, measles antibodies protect only against measles, not mumps.
