Unit 3: Neurobiology and Immunology - Key Area 7/8: Immunisation/Clinical Trials of Vaccines and Drugs

Question 1

How can immunity be developed?

Answer 1

By vaccination with antigens from infectious pathogen, so creating memory cells.

Question 2

What are the antigens used in vaccines?

Answer 2

Inactivated pathogen toxins, dead pathogens, parts of pathogens and weakened pathogens.

Question 3

What are antigens mixed with when producing the vaccine?

Answer 3

An adjuvant

Question 4

What are adjuvants?

Answer 4

Substances which make the vaccine more effective and so enhances the immune response.

Question 5

What is an example of a disease where immunity is acquired from an inactivated pathogen?

Answer 5

Diphtheria and tetanus.

Question 6

What is an example of a disease where immunity is acquired from a weakened pathogen?

Answer 6

MMR - measles, mumps and rubella.

Question 7

What is an example of a disease where immunity is acquired from a dead pathogen?

Answer 7

Poliomyelitis and hepatitis A

Question 8

What is an example of a disease where immunity is acquired from an parts of pathogen?

Answer 8

HPV against cervical cancer and hepatitis A.

Question 9

What is the difference between vaccination and immunisation?

Answer 9

Immunisation is what happens in your body after you have had a vaccination.

The vaccination which contains inactivated or weakened pathogens stimulate your immune system so that it can recognise and protect you from future infection.

Question 10

When does herd immunity occur?

Answer 10

When a critical/large percentage of a population are immunised.

Question 11

What is establishing herd immunity important for?

Answer 11

Establishing herd immunity is important in reducing the spread of diseases and in protecting vulnerable and non-immune individuals.

Question 12

How does herd immunity protect non-immune individuals?

Answer 12

If a large percentage of the population are immunised, non-immune individuals are protected as there is a lower probability that they will come into contact with infected individuals.

Question 13

What does the herd immunity threshold depend on?

Answer 13

The type of disease, the efficacy of the vaccine and the density of the population.

Question 14

When can difficulties occur with widespread vaccination?

Answer 14

It is not possible due to poverty in the developing world, or when vaccines are rejected by a percentage of the population in the developed world.

Question 15

What have some pathogens done to evade the immune system?

Answer 15

They have evolved mechanisms (changed their antigens)

Question 16

What does the fact some pathogens change their antigens mean for memory cells and what is this called?

Answer 16

They are not effective against them and this is called an antigenic mutation.

Question 17

What happens to the influenza virus which means that it is a major public health problem and how do we combat this?

Answer 17

Antigenic variation occurs. Individuals who are at risk need to be vaccinated every year because of it.

Question 18

Why are vaccines and drugs subject to clinical trials?

Answer 18

Vaccines and drugs are subjected to clinical trials to establish their safety and effectiveness before being licensed for use.

Question 19

What is the description for randomisation?

Answer 19

Randomly separated:

• test group/control group.
• similar composition e.g. gender, age, health, etc.
• eliminates bias (via computer selection/pick out of hat).

Question 20

What is the description for a placebo - control?

Answer 20

• Non effective treatment - lacks active ingredient.
• Placebo effect - thoughts/feelings.
• example could be a sugar pill.

Question 21

What is the description of a double blind trial?

Answer 21

Neither subjects or doctors know who is receiving what.

Question 22

What is the importance of group size in clinical trials?

Answer 22

Reduce experimental error and establish statistical significance.