Infection & ResponseDeep Dive
How Vaccines Work: Molecular Mechanisms
Part of Vaccination and Herd Immunity — GCSE Biology
This deep dive covers How Vaccines Work: Molecular Mechanisms within Vaccination and Herd Immunity for GCSE Biology. How vaccines work, types of vaccines, population immunity, vaccination programs It is section 3 of 14 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 3 of 14
Practice
18 questions
Recall
21 flashcards
How Vaccines Work: Molecular Mechanisms
Vaccine Principles
Vaccines work by exploiting the adaptive immune system's ability to form immunological memory. When a vaccine is administered, it presents antigens to the immune system without causing the full disease. This triggers:
- Primary immune response: B cells recognize vaccine antigens and differentiate into plasma cells producing antibodies
- Memory cell formation: Some B cells become long-lived memory B cells that "remember" the antigen
- T cell activation: Helper T cells coordinate the response, while some become memory T cells
- Rapid secondary response: Upon real pathogen exposure, memory cells rapidly produce antibodies and activate immune responses
Types of Vaccines
| Vaccine Type | Components | Advantages | Disadvantages | Examples |
|---|---|---|---|---|
| Live Attenuated | Weakened living pathogens | Strong, long-lasting immunity | Risk for immunocompromised individuals | MMR, BCG, oral polio |
| Inactivated (Killed) | Dead pathogens or components | Safe for immunocompromised | May need booster shots | Flu, hepatitis A, rabies |
| Subunit/Component | Specific pathogen proteins | Very safe, targeted | May require adjuvants | Hepatitis B, HPV |
| Toxoid | Inactivated bacterial toxins | Targets toxin-mediated diseases | Requires booster shots | Tetanus, diphtheria |