Test yourself on Vaccination and Herd Immunity with exam style questions, marked instantly.
Flashcards that come back just before you would forget them.
A revision plan that remembers what you know and shows what to do next.
See which topics you have nailed and which need another look.
Quiz yourself on Vaccination and Herd ImmunityGet your flashcardsBuild my revision planTrack my progressHow Vaccines Work
Vaccines work by triggering your immune system to produce memory cells — without you actually getting the disease. When a vaccine is given, it introduces antigens (the surface markers from a dead or weakened pathogen) into your body. Your immune system responds as though encountering a real infection:
- Antigens recognised: B cells with matching receptors are activated by the vaccine antigens.
- Antibodies produced: Activated B cells divide and some become plasma cells that make large quantities of antibodies against the pathogen.
- Memory cells formed: Some B cells become long-lived memory B cells that remain in the body for years, carrying the molecular "wanted poster" for that antigen.
- Rapid secondary response: If the real pathogen infects you later, memory cells recognise the antigen immediately and produce antibodies within 1–3 days — far faster than the 5–10 day primary response. The pathogen is destroyed before you develop symptoms.
Vaccines contain either dead or weakened pathogens, or specific proteins from the pathogen's surface. Both types introduce the antigens your immune system needs to form memory cells — without the risk of the real disease.
Make this stick
Signing in gives access to all PrepWise features.