| Passive Immunity | - Introduction of antibodies from an outside source
e.g. anti-venom for snake bites |
| Active Immunity | - Stimulation of antibodies from one's own immune system |
| Two types of active immunity | - Natural active immunity
- Artificial active immunity |
| Natural active immunity | - Individual being infected with disease under normal circumstances |
| Artificial active immunity | - Use of vaccination (immunisation)
- Introduction of a disease into the body to stimulate immune system |
| How vaccines work | - Contains antigens (dead, free, attached, attenuated - weakened - pathogen)
- Injected or taken orally
- Stimulates body to produce memory cells
- Become immune without getting symptoms |
| Boosters | - Given several years after
- Makes sure memory cells are produced |
| Disadvantages to take vaccine orally | - Could be broken down by enzymes in the gut
- Molecules may be too big to be absorbed into blood |
| Passive immunity (comparing active + passive immunity) | - Doesn't require exposure to antigen
- Protection is immediate
- Memory cells aren't produced
- Protection is short-term, antibodies broken down |
| Active immunity (comparing active + passive immunity) | - Requires exposure to antigen
- Protection not immediate
- Memory cells are produced
- Protection is long-term, antibody produced |
| Herd Immunity | - Vaccinating most of a population so that no-one has the disease and transmission is stopped |
| Why vaccination may not eliminate a disease | - Agentic variability
- Individuals with defective immune systems - cannot become immune |
| How antigenic variation helps pathogens evade immune systems | - When infected a 2nd time by same pathogen
- Memory cells will not recognise different antigens
- Carry out primary response again, takes time, get ill |
| How antigenic variation effects vaccines | - Antigens change regularly
- Forming new strains
- Antibodies dont recognise different antigen in vaccine |
| Ethics of vaccines | - Tested on animals
- Can cause long-term side effects
- Volunteers putting themselves at unnecessary risk |
| The MMR vaccine (study) | - Study about safety of measles, mumps and rubella vaccine
- Based on 12 children with autism
- Links autism + vaccine |
| Validity and reliability of findings | - Very small sample (12 children), results due to chance
- Biased, one scientist involved was helping to gain evidence for a lawsuit against MMR vaccine manufacturer
- Many studies prove theory wrong |
| Further studies | - 2005 study in Japan
- Looked at medical records of 30 000 children between 1988 + 1996 - jab was introduced
- Counted number of children that developed autism before age of 7 |
