Vaccination Flashcards
What is a vaccine?
A substance used to stimulate the production of antibodies and provide immunity against one or more diseases
What is the aim of immunisation?
To provoke immunological memory and protect individuals against a particular diseases if encountered
What are some characteristics of the ideal vaccine?
Safe Easy to administer Cheap Can be stored for longer periods of time Active against all variants Life-Long protection
What three things can vaccines work to do?
- Prevent entry - vaccine stimulates production of antibodies which bind to virus and stop it harming cells
- Boosting immune response - the antigens in the vaccine stimulate CD4 Helper T cells
- Killing Infected cells - CD8 killer cells detect the foreign antigens
What are the characteristics of immune memory?
The memory cells can multiply much faster and produce a stronger immune response by generating antibodies which have a higher affinity for antigens
What is R0?
The basic reproduction number - the number of cases one case generates on average over the course of their infectious period
What happens if R0 <1?
The infection will die out ebventually
What happens if R0>1?
Then the infection will be able to spread in the population
What is the effective number and why is it more useful?
It is similar to R0 but does not assume that everyone is susceptible, and therefore takes into account that people may be immune - helpful as then the true severity can be determined
What is herd immunity?
Those people who are immunised against the virus can help protect those who are not as the virus will be less transmissible amongst those protected
What are the four components of a vaccine?
antigen
adjuvant
stabilising factors eg buffers
water
What is an adjuvant?
Substances used alongside the antigen to illicit a more robust immune response than if the antigen was just used alone
How do adjuvants work?
They engage with pattern recognition proteins which induce danger signals that activate DC’s to present antigen to T cells
What adjuvant is normally found in vaccines?
Alum
Mechanism of adjuvant action?
- Adjuvant stimulates DC
- DC take up antigen and moves to secondary lymphoid tissue
- Upregulation of co-stimulatory signalling and cytokines