Natural/Passive Iummunity Flashcards
What isa vaccine?
a way of introducing antigens of a dead or weakened pathogen into the body to stimulate the production of antibodies and memory cells
How are pathogens prepared for viruses made harmless?
Killing but leaving antigens unaffected
Weakening but leaving antigens unaffected
Purified antigens removed from pathogen
Using inactivated toxins( toxoids) that are harmless but trigger same immune response
What are the ethical issues with vaccine?
Vaccines are tested on animals first
Humans in clinical trials may put themselves at risk because they believe they may be ‘immune’
Fears of side effects
Why don’t vaccinations fully eliminate diseases?
Fails to induce immunity in some people( immunodeficiency)
People get infected before enough Abs are generate by vaccine to afford protection
Antigenic Variability- pathogens can mutate
Many different strains
Objections to vaccinations based on moral, religious and ethical grounds
What is Herd Immunity?
a population can be protected from a certain virus if a threshold of vaccination is reachedHo
How is Herd Immunity achieved?
vaccinating a large amount of the population so that enough people are immune to the virus it cannot spread far through the population
What is Natural active immunity?
you become immune after catching the disease
What is Artificial active immunity?
you become immune after being given a vaccination containing harmless dose of the antigen
What is Natural passive immunity?
a baby gets antibodies through placenta and in breast milk
What is Artificial passive immunity?
you are injected with antibodies
What are the problems with passive immunity?
Maternal antibodies pass from placenta into foetal blood
Breast feeding passes antibodies present in the colostrum
Protection is temporary and only lasts few months after birth
