5.6 - Vaccination Flashcards
What is immunity?
The ability of an organism to resist infection
What are the two forms of immunity?
- Passive immunity
- Active immunity
What are the two types of active immunity?
- Natural
- Artificial
What is passive immunity?
It is produced by the introduction of antibodies into individuals from an outside source, so no direct contact with the pathogen or its antigen. Because the individual doesn’t produce the antibodies themselves when they are broken down they are not replaced - so no long lasting immunity
Give an example of passive immunity
Anti-venom given to victims of snake bites
What is active immunity?
It is produced by stimulating the production of antibodies by the individuals own immune system - direct contact with the pathogen or its antigen is necessary
What is natural active immunity?
Results from an individual becoming infected with a disease under normal circumstances - the body produces its own antibodies and may continue to do so for many years - long lasting immunity
What is artificial active immunity
Vaccination - involves inducing an immune response in an individual, without them suffering they symptoms of the disease.
What is Vaccination?
The introduction of the appropriate disease antigens into the body, either by injection or by mouth, the injection is to stimulate an immune response against a particular disease
Why is the reponce only slight from a vaccination?
Because only a small amount of antigen has been produced
How does a vaccination stop future disease?
It creates memory cells which stay in the blood and allow a greater, and more immediate, response to a future infection with the pathogen
When does herd immunity arise?
When a sufficiently large proportion of the population has been vaccinated to make is difficult for a pathogen to spread within that population
How are the people who are not vaccinated in herd immunity protected?
Because it is highly improbable that a non vaccinated individual will come in contact will an infected person because nearly everyone is vaccinated
Why is herd immunity important?
Because it is never possible to vaccinate everyone in a large population
Why cant you vaccinate everyone?
- babies and young children are not vaccinated because there immune system is not yet fully functional
- dangerous to vaccinate people who are ill or who have a compromised immune system
Give six reasons why vaccination may not eliminate disease
- Vaccinations fails to induce immunity to certain individuals E.g people with defective immune systems
- Individuals may develop the disease immediately after vaccination but before their immunity levels are high enough to prevent it
- Pathogen might mutate frequently making the vaccine ineffective
- There may be so many varieties of a particular pathogen that is is almost impossible to develop a vaccine that is effective against them all
- Certain pathogens hide from the bodies immune system - by concealing themselves inside cells or living in places out of reach (intestines)
- Individuals may have objections to vaccinations for religious, ethical or medical reasons
