Unit Three - Key Area 7

Question 1

How can immunity be developed?

Answer 1

Immunity can be developed by vaccination using antigens from infectious pathogens, so creating memory cells.

Question 2

What are antigens used in vaccinations?

Answer 2

Antigens used in vaccinations can be inactivated pathogen toxins, dead pathogens, parts of pathogens and weakened pathogens.

Question 3

What are adjuvants?

Answer 3

Adjuvants are a substance which makes the vaccine more effective, so enhancing the immune response. Antigens are usually mixed with an adjuvant during production.

Question 4

What is herd immunity and why is it important?

Answer 4

Herd immunity occurs when a large percentage of the population is immunised. Establishing herd immunity is very important in reducing the spread of diseases.
Non-immune individuals are protected as there is a lower probability they will come into contact with infected individuals.

Question 5

What issues can arise with mass vaccination programmes?

Answer 5

Widespread vaccination may not be possible due to malnutrition and poverty levels in some countries. Vaccines may also be rejected by a percentage of the population. This may be due to adverse publicity about the vaccine.

Question 6

What is antigenic variation?

Answer 6

Some pathogens have the ability to alter their antigens. As a result, memory cells do not detect the altered antigens and are no longer effective against the pathogen.