Immunisation Flashcards
How is immunity developed
by vaccination
What part of a pathogen could be given to a person to stimulate immunity
antigens from infectious pathogens, thus creating memory cells
Antigens used in vaccines can be
inactivated pathogen toxins
dead pathogens
parts of pathogens
weakened pathogens
What is an adjuvant
a substance which makes the vaccine more effective
Explain why an adjuvant is added
to enhance the immune response
What is herd immunity
when a large percentage of a population are immunised
Why is it important to establish herd immunity
to reduce the spread of diseases
How is the spread of diseases reduced
non immune individuals are protected as there is a lower probability that they will come into contact with infected individuals
What does the herd immunity threshold depend on
type of disease
efficacy of the vaccine
density of the population
How do some pathogens avoid the effect of memory cells
pathogens change their antigens so memory cells are not effective against them
What is the herd immunity threshold
the percentage of immune individuals in a population above which a disease no longer manages to persist
Difficulties can arise when widespread vaccination is not possible due to
poverty in the developing world
when vaccines are rejected by a percentage of the population in the developed world
Some pathogens can change their antigens what does this mean
memory cells are not as effective against them
Describe how memory cells lead to an increase in antibody production
after the individual has been exposed to a virus
rapidly produce a new clone of specific lymphocytes
