Vaccination Flashcards
What is passive immunity?
- it’s produced by the introduction of antibodies into individuals from an outside source
- no direct contact with the pathogen or antigen is necessary to induce immunity
- immunity is acquired immediately
- antibodies are not replaced when they are broken down no more memory cell are formed and so there is no lasting immunity
What is an example of passive immunity?
- anti venom given to victims of snake bites
- the immunity acquired by the fetus when antibodies pass across the placenta from the mother
What is active immunity?
- it’s produced by stimulating the production of antibodies by the individuals own immune system
- direct contact with the pathogen or its antigen is necessary
What are the types of active immunity?
- natural active immunity
- artificial active immunity
What is natural active immunity?
- results from an individual becoming infected with disease under normal circumstances
- the body produced its own antibodies and may continue to do so for many years
What is artificial active immunity?
- forms the basis of vaccination
- it involves inducing an immune respond in an individual without them suffering symptoms of the disease
What is a vaccination?
- the introduction of the appropriate disease antigens into the body either by injection or by mouth
- the intention is to stimulate an immune response against a particular dies was
What are the forms of immunity?
- passive immunity
- active immunity
What is a vaccine?
- the material introduced in a vaccination which contains one or more types of antigen from the pathogen
- these antigens stimulate the immune response
Why are vaccines and vaccinations important?
-although the response to the small amount of antigen introduced is slight the memory cells that are produced are able to remain in the blood and allow a greater and more immediate response to a future infection with the pathogen which results in a rapid production of antibodies and the new infection if rapidly overcome before it can cause any harm with few symptoms
Which factors create a successful vaccination programme?
- a suitable vaccine must be economically available in sufficient quantities to immunise most of the vulnerable population
- there must be few side effects from vaccinations as unpleasant side effects may discourage individuals from the population getting vaccinated
- a means of producing, storing and transporting the vaccine must be available like technologically advanced equipment, hygienic conditions and refrigerated transport
- there must be means of administrating the vaccines properly at the appropriate time involving skilled staff at different centres
- it must be possible to vaccinate the vast majority of the vulnerable population to produce herd immunity
How does herd immunity take place?
-it arises when a sufficiently large proportion of the population has been vaccinated to make it difficult for the pathogen to spread within the population which is based on the idea that pathogens are passed from individual to individual when in close contact so when the majority of the population is immune it’s highly improbable that a susceptible individual will come into contact with an infected person so people not immune are protected
Why may vaccines not fully eliminate a disease?
- vaccination fails to induce immunity in individuals with defective immune systems
- individuals may develop the disease just after receiving the vaccine so can’t be prevented in time
- antigenic variability occurs
- there could be so many varieties of a particular pathogen that it’s almost impossible to develop a vaccine that’s effective against them all
- certain pathogens hide from the body’s immune system by concealing themselves inside cells out of reach of the immune system
- individuals may be opposed to vaccines based on their own beliefs which happened when parents opted out of giving their kids the MMR vaccine
What are the ethics of using vaccinations?
- is the production and development of vaccines ethical if it involves animal testing
- vaccines have side effects that can cause long term harm so is it worth it
- who should the vaccine be tested on
- how should trials be carried out
- to what extent should individuals be asked to accept risks for public health
- is it acceptable to trial a vaccine in a country simply because it has more to gain if it’s successful
- should vaccinations be compulsory If so when and can people opt out of so on what grounds
- should expensive vaccine programmes continue when a disease is almost eradicated even though there’s less money to treat others
- how can any individuals health risked from vaccination be balanced against the advantage if controlling the disease for the larger population
What is antigenic variability?
-vaccines suddenly become ineffective as the pathogen mutates frequently to the point where it is unrecognisable to the immune system and the antibodies required are not produced like with the influenza virus
