Vaccination Flashcards
What is passive immunity?
- Produced by the introduction of antibodies from an outside source.
- No direct contact with pathogen or antigen is necessary to induce immunity.
- Immediate immunity and no memory cells are formed so it is not long lasting.
What is active immunity?
- Produced by stimulation of antibody production by the individuals own immune system.
- Direct contact with pathogen or antigen is necessary, immunity takes time to develop but last longer.
What are the two types of active immunity?
Natural Active Immunity - individual becomes infected with disease under normal circumstances. Body produces own antibodies.
Artificial Active Immunity - Forms the basis of vaccination (immunisation). Involves inducing an immune response in an individual without them suffering with symptoms of disease.
What does a vaccination do?
Antigens are given to the human which stimulate an immune response. Memory cells are produced which remain in the blood and allow for a greater and more immediate response to the same antigen in the future. A rapid production of antibodies and the new infection is rapidly overcome before it causes harm with any symptoms.
What are the features of a successful vaccination programme?
- Economically available in sufficient quantities to immunise most of vulnerable population.
- Few side effects. Side effects may discourage people from being vaccinated.
- Means of producing, storing and transporting the vaccine available.
- Means of administering vaccine at an appropriate time at places throughout population distribution.
- Possible to vaccine majority of population to produce herd immunity.
What is herd immunity?
Arises when a sufficiently large proportion of the population have been vaccinated, making it difficult for a pathogen to spread within population.
Why is herd immunity important?
It is never possible to vaccinate everyone in a large population so by vaccinating a large proportion, it reduces the chance of someone coming into contact with an infected person and therefore spreading it.
Why can’t vaccines be given to the entire population?
- Babies and young children have too weak immune system to fight of pathogen.
- People with compromised immune systems
Why may a vaccine not always eliminate a disease?
- Fail to induce immunity in individuals with defective immune systems.
- Individuals may develop disease immediately after vaccination where immunity levels aren’t high enough.
- Pathogen may frequently mutate, meaning the vaccine becomes ineffective quickly and a new one has to be rapidly developed and administered.
- May not be possible to immunise against some pathogens.
- Individuals may object to being vaccine, for medical, ethical or religious reasons.
What are some of the raised issues of vaccines?
- May involve the use of animals to develop and produce vaccines.
- Some side-effects of vaccines may cause long term harm.
- Worries of vaccine trials carried out on animals and humans.
- Some people may decline vaccination on medical, religious or ethical grounds.
- How can individual health risks be balanced against risks to the entire population?
