Vaccines

Question 1

What is a vaccine?

Answer 1

A preparation of antigen from a pathogen that will generate a primary immune response when injected into an individual but will not cause the disease.
—> antibodies and memory cells are produced

Question 2

What are the different types of vaccines?

Answer 2

1. Killed pathogen
2. Attenuated live virus
3. Toxin
4. Isolated pathogen antigens
5. Genetically engineered antigens

Question 3

How does vaccination protect against disease?

Answer 3

1. Vaccination given
2. Primary immune response occurs
   —> T cells, b cells activated
3. Memory B and T cells are produced (protects vaccine recipient)
4. Person is infected with disease and memory cells are activated.
5. Secondary immune response occurs
   —> Very fast immune response - pathogen killed quickly before symptoms occur.

Question 4

What is herd immunity?

Answer 4

Most of the population is vaccinated/ immune.

Question 5

When is vaccination not successful?

Answer 5

1. Certain people have weak immune systems
2. Memory cells eventually die
3. Pathogens can show antigen variability
4. When individuals opt out of vaccination (due to fear of side effects)

Question 6

Describe the two types of passive immunity.

Answer 6

1. Natural
   - when a baby receives antibodies from its mother (via placenta or from breast milk)
2. Artificial
   - when you are injected with antibodies from someone else (from blood donations)

Question 7

Describe the two types of active immunity.

Answer 7

1. Natural
   - when you become immune after infection by a pathogen (primary immune response)
2. Artificial
   - when you become immune after vaccination

Question 8

Compare passive and active immunity.

Answer 8

1. Passive immunity doesn’t require exposure to antigen, active immunity does.
2. Protection is immediate with passive immunity, it takes a while to develop with active immunity.
3. Passive immunity does not produce memory cells, active immunity does.
4. With passive immunity, protection is short term as the antibodies given are broken down but with active immunity, protection is long term as the presence of memory cells means a secondary immune response can take place.