immunisation 3.7 Flashcards
how is immunity developed
by vaccination using antigens from infectious pathogens which creates memory cells
what antigens can be used in vaccines
- inactivated pathogen toxins
- dead pathogens
- parts of pathogens
- weakened pathogens
what are antigens mixed with when producing a vaccine
usually mixed with an adjuvant
what’s an adjuvant
a substance which makes the vaccine more effective, therefore enhancing the immune system
when does herd immunity occur
when a large percentage is immunised
why is herd immunity important
for reducing the spread of disease
why are non immune individuals protected
there’s a low probability they will come into contact with infected individuals
how is herd immunity achieved
mass vaccination programs
how can herd immunity be hard to obtain
when widespread vaccination is not possible due to poverty in developing world or when vaccines are rejected by a percentage of the population in the developing world
what does the herd immunity threshold depend on
the type of disease, the effectiveness of the vaccine and the density of the population
what happens when pathogens change their antigens
the memory cells aren’t effective against them
