3.7- immunisation

Question 1

what is immunisation?

Answer 1

process where a person develops immunity to a disease-causing organism

Question 2

what is active immunity?

Answer 2

the protection gained as a result of the person’s body producing its own antibodies

Question 3

how does a person gain immunity by natural means?

Answer 3

through immunological memory

if initial exposure to an infection is survived, subsequent exposure to the same antigen at a layer date results in the secondary response, preventing the disease from recurring

Question 4

what does a vaccine use?

Answer 4

uses antigens from infectious pathogens to create memory cells

Question 5

what can the antigens used in a vaccine be?

Answer 5

inactivated pathogen toxins

dead pathogens

parts of pathogens

weakened pathogens

Question 6

3 ways vaccines are introduced into the body

Answer 6

injection

ingestion

nasal spray

Question 7

what is an antigen usually mixed with?

Answer 7

adjuvant

Question 8

what is an adjuvant?

Answer 8

chemical substance

Question 9

what 2 things does the changed antigen cause in each vaccination case?

Answer 9

production of B and T cells

the formation of antibodies but does not cause the disease

Question 10

what do some B and T cells persist in the body as and what do they do?

Answer 10

memory cells

initiate secondary response if person is exposed to the normal disease-causing antigen at a later date

Question 11

when does herd immunity occur?

Answer 11

when a large percentage of the population is immunised

Question 12

how are non immune individuals protected in herd immunity?

Answer 12

there is a lower probability they will come into contact with infected individuals

disrupts normal chain of infection

Question 13

what makes herd immunity effective?

Answer 13

only a minority of the population can be left unvaccinated

Question 14

what is the herd immunity threshold?

Answer 14

the percentage of immune individuals in a population above which a disease no longer manages to persist

Question 15

3 factors that alter the value of the herd immunity threshold

Answer 15

virulence of pathogen (capacity for causing disease)

vaccines effectiveness

density of population

Question 16

2 difficulties surrounding mass vaccination

Answer 16

poverty in developing world

rejection of a percentage of the population in the developed world

Question 17

when does a persons vaccination schedule usually begin in the UK?

Answer 17

2 months

Question 18

5 vaccinations you receive in the UK

Answer 18

influenza

whooping cough

tetanus

poliomyelitis

diphtheria

Question 19

why might herd immunity be compromised in developed countries?

Answer 19

if parents believe adverse publicity and refuse to have their children vaccinated

Question 20

what happens within a population of pathogenic microorganisms?

Answer 20

new strains arise continuously by mutation

Question 21

what are the new strains described as showing and why?

Answer 21

antigenic variation

if they have antigens on their surface that are different from the original strain

Question 22

what are the new strains of pathogens showing antigenic variation said to be and why do they work?

Answer 22

genetically and immunologically distinct from parent strain

succeed as it employs a selective advantage

Question 23

what effect do new antigens have on the influenza virus?

Answer 23

enable it to avoid effects of the human body’s immunological memory

Question 24

how do new antigens disabling immunological memory allow influenza reinfect a person?

Answer 24

new antigens are not recognised by their memory cells