3.7 Flashcards
what do vaccinations do
devleop immunity using antigens from infectious pathogens which creates memory cells
what are the antigens in vaccines
they can be inactivated pathogen toxins, dead pathogens, parts of pathogens and weakened pathogens
what are antigens mixed with in a vaccine
an adjuvant
what is an adjuvant
a substance which makes the vaccine more effective which enhanced the immune response response
when does herd immunity occur
when a large percentage of a population is immunised
why is establishing herd immunity important
to reduce the spread of diseases
how does herd immunity protect non immune individuals
because it means there is a low probability of them coming into contact with infected individuals
what is the purpose of mass vaccination programs
to establish herd immunity to a disease
why might difficulties surrounding widespread vaccination occur
- due to poverty in the developing world
- when vaccines are rejected by a % of the population in the developed world
what does the herd immunity threshold depend on
- the type of disease
- the effectiveness of the vaccine
- the density of the population
can some pathogens change their antigens
yes
what happens when pathogens change their antigens
memory cells aren’t effective against them
give an example of a virus where antigenic variation occurs
the influenza virus
why is the influenza virus a public health problem
because antigenic variation occurs meaning individuals who are are risk need to be vaccinated every year
