Immunisation

Question 1

How is immunity developed?

Answer 1

Immunity is developed by vaccinations using antigens from infectious pathogens, so creating memory cells

Question 2

What are antigens?

Answer 2

In vaccinations they can be inactivated toxins, dead pathogens, parts of pathogens and weak pathogens.

Question 3

Explain what an adjuvant is and what it does:

Answer 3

It is usually mixed with antigens during production. They are a substance that makes vaccines more effective, so enhancing the immune response.

Question 4

Give an example of an adjuvant:

Answer 4

an alluvium mineral based adjuvant is added to the hepatitis A vaccine.

Question 5

When does herd immunity occur?

Answer 5

When a large percentage of the population is vaccinated.

Question 6

Why is herd immunity important?

Answer 6

To reduce the spread of diseases.

Question 7

How does herd immunity work?

Answer 7

Non-immune individuals are protected as there is a lower probability they will come into contact with the infected individuals.

Question 8

List the factors herd immunity depend on:

Answer 8

• type of disease
• effectiveness of vaccine
• density of population

Question 9

What are two reasons for why mass vaccination is sometimes not possible?

Answer 9

1. Poverty in developing world
2. Vaccines are rejected by a large volume of people in the developed world.

Question 10

What does antigenic variation mean?

Answer 10

Some pathogens can change their antigens. Means that memory cells are not effective against them.

Question 11

What is an example of antigenic variation?

Answer 11

The influenza virus, continues to be a major health problem each year. This is why individuals at risk need to be vaccinated every year.

Question 12

What is the purpose of clinical trials?

Answer 12

Clinical trials are needed to establish safety and effectiveness before being licensed for use.

Question 13

What are 3 factors in setting up a clinical trial?

Answer 13

1. Randomised
2. Double - blind
3. Placebo - controlled

Question 14

Explain each of these factors:

Answer 14

Randomised - reduces the bias in the distribution of characteristics such as age and gender.
Double-blind - Neither subjects nor researchers know which group subjects are in to prevent biased interpretation of results.
Placebo-controlled - One group of subjects receives the vaccine/drug while the other receives a placebo-control to ensure valid comparisons

Question 15

Why is group size important?

Answer 15

To reduce experimental errors and establish a statistical significance.