Vaccination Flashcards
What are the two types of immunity?
• Passive immunity
• Active Immunity
- Natural Active immunity
- Artificial Active Immunity
What is passive immunity?
- Immunity produced by the introduction of antibodies into individuals from an outside source.
- No direct contact with the pathogen ( or it’s antigen ) is necessary to induce immunity, immunity is attained instantly.
What are some disadvantages to passive immunity?
- Anti-bodies are not being produced by the body.
- No memory cells are formed, so there is no lasting immunity.
- Antibodies are not replaced, since the individual is not producing the antibodies themselves.
What is active immunity?
- Produced through the stimulation of the immune system by the individuals own immune
- Contact with the pathogen, or it’s antigen is necessary.
What are the two types of active immunity?
- Natural Active Immunity
* Artificial Active Immunity
How is natural active immunity attained
- Caused through a person becoming infected with a disease under normal circumstances.
- The individual’s body produces its own antibodies.
How is artificial active immunity gained?
It is when an immune response is stimulated after being given a vaccination containing a harmless dose of antigen.
What is natural passive immunity?
• When a baby becomes immune due the antibodies it receives from it’s mother, through the placenta and in breast milk.
What is artificial passive immunity?
• When you become immune after being injected with antibodies from someone else.
What s the purpose of vaccination?
- Vaccines contain antigens that cause your body to produce memory cells against a particular pathogen, without the pathogen causing disease, resulting in immunity without getting any symptoms.
- Stimulate immune response against a disease.
What do vaccines contain?
Antigens, that can be free or attached to a dead or weakened pathogen.
What are the two methods of taking vaccines?
- Orally
* Injection
What is a disadvantage to taking vaccines orally?
- Broken down by enzymes in the gut
* Molecules of the vaccine may be too large to be absorbed into the blood.
How does antigenic variation result in receiving the same infection twice?
- Pathogens can change their surface antigens, this is antigenic variation, different antigens are formed due to changes in the genes of a pathogen.
- When you receive the infection a second time, the memory cells produced from the first infection will not recognise the different antigens, so the immune system has to start from scratch and carry out a primary response against the new antigens.
- Primary response takes time to get rid of the infection, which results in the illness again.
What is antigenic variation?
Pathogens changing their surface antigens, the different antigens are formed due to changes in the genes of a pathogen.
What are some differences between passive and active immunity?
Active Immunity: • Requires Exposure to antigen • Takes longer for protection to develop • Memory cells are produced • Protect ion is long term because the antibody is produced in response to complementary antigen being present in the body. Passive Immunity: • Doesn't require exposure to antigen • Protection is immediate • Memory cells aren't produced • Protection is short term because the antibodies given are broken down.
What are the features of a successful vaccination program?
- A suitable vaccine must be economically available in sufficient quantities to immunise most of the vulnerable population.
- Few side effects, side effects may discourage people to vaccinate
- Production, storage and transportation of vaccine must be available.
- Means of administering the vaccine must be properly available and at an appropriate time.
- It must be possible to vaccinate a majority of the vulnerable population to produce herd immunity.
When is herd immunity achieved?
When a large proportion of the population has been vaccinated, in order to make it difficult for a pathogen to spread within that population.
What is herd immunity?
Reducing the occurrence of the disease, so that those that are not vaccinated are also less likely to catch the disease, due to a fewer number of people to catch it from.
What are some reasons that a vaccination may not fully eliminate a disease?
- Vaccination may fail to induce immunity in some people, e.g. those with defective immune systems.
- Individuals may develop the disease immediately after vaccination but before their immunity levels are high enough to prevent it, these people may infect others.
- Pathogen may frequently mutate, making vaccinations ineffective because they are no longer able to used to get rid of the pathogen.
- They may be such a large number of varieties of a particular pathogen that it is almost impossible to develop a vaccine that is effective against them all.
- Pathogens may hide from the body’s immune system, through concealing themselves inside the cell, making it difficult to target them.
- People may not take vaccinations due to religious, ethical or medical reasons.
What are some ethical issues with using vaccinations?
- Production of existing vaccines uses animals, there are concerns over the health of animals.
- Vaccines sometimes have side effects that can cause long term harm.
- Issues over who vaccines should be tested upon, testing vaccines on humans can result in putting people at unnecessary risk of contracting disease.
- Difficult decisions may made about how would be the first to receive the vaccine in an outbreak.
