3.7 Immunisation

Question 1

Immunity

Answer 1

Can be developed by vaccination using antigens from infectious pathogens, therefore creating memory cells.

Question 2

Vaccines

Answer 2

Can contain inactivated pathogen toxins, dead pathogens, parts of pathogens or weakened pathogens.

Question 3

Enhancing the Immune Response

Answer 3

Antigens are usually mixed with an adjuvant when producing the vaccine to enhance the immune response.

Question 4

Herd Immunity

Answer 4

Occurs when a large percentage of a population are immunised.
Establishing herd immunity is important in reducing the spread of diseases.
Non-immune individuals will be protected due to a lower chance of them coming into contact with infected individuals.

Question 5

Herd Immunity Threshold

Answer 5

Depends on the type of disease, the efficacy of the vaccine and the density of the population.

Question 6

Mass Vaccination Programmes

Answer 6

Dessigned to establish herd immunity to a disease.

Question 7

Difficulties in Establishing Widespread Vaccination

Answer 7

Includes poverty in the developing world and rejection of the vaccine by a percentage of the population in the developed world.

Question 8

Antigenic Variation

Answer 8

When some pathogens (e.g. influenza) change their antigens. This means memory cells are not effective against them.
Antigenic variation occurs in the influenza virus explaining why it remains a major public health problem and why individuals who are at risk need to be vaccinated every year.