Vaccines Flashcards
Two types of immuity
- passive immuity
- active immunity
What is pasisve immunity
When you dont actually create antibodies yourself and instead pathogens are introduced into your body
Why don’t your have long-term immunity with passive immunity
Because the pathogen doesn’t enter the body no memory or B cells are made so therefore the individual has no long-term immunity
Examples of passive immunity
- maternal antibodies
- anti - venom
What are maternal antibodies
Antibodies that are passed on to the fetus through the placenta or breast milk
What is anti-venom
A form of pasisve immunity and is given to a a victim of snake bites to destroy toxins
What is active immunity
Creates antibodies yourself by exosing your immune system following expose to pathogens or its antigens
2 types of active immuity
- natural active immunity
- artificial active immunity
What is natural immunity
Folloiwng an infection body creates own antibodies and memory cells
What is artifical active immunity
Weakend or dead version pathogen/antigen enter the body via vaccination
How do vaccines work
Deliberately exposing a perosn to antigenic materil which is rendered harmless whic stimulates an immune response as the antigentic material is treated as a real pathogen and a primary response occurs
Stages of a vaaccination response
- exposure to the antigen actives B cells to go through clonal selection
- B cells undergo mitosis to make a large number of cells
- these differtiate into plamam and menory cells
- memory B cells can divide rapidly into plasma cells when re-infected by same pathogens
What is herd immunity
Enough of the population vaccinated the pathogen cannot spread easily throughout the population. It provides protection against those who are not vaccinated
What type of people cannot be vaccinated
- too ill
- too young - immune system not fully functional
- elderly people
What is antigen variablity
Pathogens DNA can mutate frequently so muations occur within the gene that codes for antigens which causes the shape of the antigen to change so pevious immunity is no longer effective as memory cells will have memory of old antigen shape.
Why do we need a new vaccine every year for flu
Because the flu pathogen mutates frequently which cause the gene which codes for antigens to mutate causing the shape of the antigen to change shape meaning previous immunity no longer effective because memory cells have the memory of the old antigen shape
Ethics of vaccines
- use of animal
- side effects
- cost
- should it be made compulsory
- testing vaccines
How can we trust scientists
- peer reveiw
- source of funding
- personl beliefs
- medi presentation
- new theories may challenge to beliefs
Features of successful vaccintion
- Economic
- few side effects
- easy to produce and store
- easy too administer
- herd immunity
Features of an unsuccessful vaccination-
- defective immune system
- develop the disease after vaccination
- antigentic variability
- too many varieties
- objections
