Vaccination Flashcards
Purpose of vaccination?
Vaccination is the generation of
Immune Memory in the absence of harmful infection
What is the R number?
Number of cases one case generates on average over the course of infectious period.
What R number means disease will spread?
R > 1
What R number means disease will eventually die out?
R < 1
What does the R number mean for vaccination?
A higher R number means you will need higher herd immunity.
What are the 5 types of vaccines?
Inactivated Toxoid vaccine
Recombinant protein vaccine
Conjugate vaccine
Dead pathogen vaccine
Live attenuated vaccine
How does the inactivated toxoid vaccine work?
Chemically inactivated form of toxin. Induces antibody response as antibody blocks toxin.
Advantages of inactivated toxoid vaccine?
Cheap and safe.
Disadvantage of inactivated toxoid vaccine?
Only can be produced if pathogen produces a toxin.
How are Recombinant protein vaccines produced?
Surface antigen gene is isolated. Gene is inserted to the yeast cell DNA. Yeast produces antigen. Antigen is purified and use in vaccine.
Advantages of recombinant protein vaccines?
Safe.
Disadvantages of recombinant protein vaccines?
Relatively expensive and not very immunogenic.
What challenge is present when making vaccines for bacteria? What type of vaccine overcomes this challenge?
Bacterial often have a capsule which is made of a polysaccharide. This is not very good at inducing a B cell response since it is a thymus independent antigen. Conjugate vaccines.
How do conjugate vaccines work?
Polysaccharide coat is coupled to an immunogenic carrier protein. Protein enlists CD4 cells to boost B cell response to polysaccharide.
Advantages of conjugate vaccines?
Highly effective at controlling bacterial infection.
Disadvantages of conjugate vaccines?
Cost, carrier protein interference, very strain specific.
How do dead pathogen vaccines work?
Chemically killed pathogen that induces antibody and T cell responses.
Advantages of dead pathogen vaccines?
Immunogenic as you leave antigenic components intact and in context of other antigen. Cheap. Quick.
Disadvantages of dead pathogen vaccines?
Pathogen needs to be grown, antigenic drift can occur when grown and chemicals can also alter the antigen(not same pathogen that is present in population).
How do live attenuated vaccines work?
Pathogen continually grown and mutated until it loses its virulence. Can be given to individual and can replicate.
Advantages of live attenuated vaccines?
Can trigger a strong immune response and provides immunity in local site of infection.
Disadvantages of live attenuated vaccines?
Can affect immunocompromised badly and could revert to virulence. Attenuation may lose key antigens.
What do adjuvants do and how do they work?
Present in vaccines and give a more robust immune response. They do this by inducing danger signals that activate dendritic cells and these can present antigen to T cells. Upregulates stimulatory cytokines.
Why do we need new vaccines?
Aging population. New diseases. Antibiotic resistance.
Barriers to future vaccines?
Cold chain and cost. High variation in target organism (HIV).
Vaccines against viruses are usually of what type?
Either live-attenuated or killed.
