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level: 5.6 Vaccination

Questions and Answers List

level questions: 5.6 Vaccination

QuestionAnswer
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