Vaccinations: Concepts, principles and details Flashcards
The concept of herd immunity means _
Disease reintroduction doesn’t lead to spread of disease
Eradication of an organism (virus) requires 4 things. They are _
Low antigenic drift / strains of virus
No animal reservoir
Early diagnosis of new cases
High collaboration
Current vaccines what best for intracellular or extracellular bacteria?
Extracellular
2 major goals of vaccinations are _
Antibody response
Memory
A good vaccine will _
Mimic route of delivery
Current vaccines target _ types of structures on bacteria. What are the examples provided (3)
External structure
Capsular poly saccharides
Surface proteins
LPS
Regarding whole organism vaccines, a pro and a con are _
Broadest immune response
More potential toxicity
Compared to whole organism vaccines, purified proteins are {more/less] toxic, [more/less] protective]
Less
Less
A major draw back to using purifed protein as a vaccine is _
Genetic variation between strains, if protein switches, no longer immune
Pure capsular polysaccharides elicit what type of immune response? What population would this type of vaccine be ineffective for/
T-independent.
Children under 2
What problem to conjugate vaccine solve?
Get children under 2 to develop immunity to calsular polysaccharides
What type of antibody is most likely to effectively engage / activate the complement system?
IgM
What is a serotype?
A natural product of genetic mutation
Why is a whole cell vaccine better than a purified protein?
You generate antibodies to various component of the bacteria. Protects agains serotype switching, as you have antibodies to various components of the bacteria
Under what circumstance is IgG able to effectively activate the complement cascade?
Requires high density of the surface antigen. Antigens can be different
Pure polysaccharides are detected by what type of immune response? What is the product of this response? What is a major limitation
T-independent
IgM antibodies
No memory
2 major advantages of the T-dependent response are _
Able to respond to intracellular pathogens
Long term memory
How to APC respond to a pure polysaccharide antigen?
No response. Cannot present the peptide on MHC
What is the immune response to a pure polysachharide antigen? What is the mediating cell? Product?
T-independent
B cells
IgM and some IgG
A way to circumvent the inability to respond to pure polysaccharide antigens is via _
Conjugate vaccines
The example provided where conjugate vaccines reduced incidence in iowa was of _
Bacterial meningitis
An example of a vaccine that uses a toxoid is _
Tetanus
2 examples where a live attenuated vaccine is used are _. What are contraindications?
Measles
Polio
Can’t use in immune suppressed, including pregnancy
3 examples of inactivated vaccines are _
Influenza
Rabies
Hep A
3 examples of subunits of the vaccine being used are _
Hep B
Pertusis
Tetanus
3 examples of conjugate vaccines are _
Hemophilus Influenza
Strep Pneumo
Nisseria Meningiditis
What 3 vaccines are required of healthcare personnel?
Varicella Zoster
Hep B
Influenza (Annual)
The primary response to a toxin occurs over what time frame? What is the main product?
7-10 days
IgM
The secondary response to an initial exposure to a toxin occurs over what time frame? What is the main product
2 weeks
IgG
What antibodies are increased during the primary phase of the immune response? Secondary phase?
IgM
IgG
These can be used clinically to determine disease phase
What is the source of any IgM found in the fetus? Why?
From fetus. IgM doesn’t cross membranes
What is the source of IgG in the fetus?
Maternal and fetal. IgM is able to cross membrane
What is the source of IgA in the fetus?
From fetus. IgM doesn’t cross membranes
What is the significance of high IgM in the fetus?
Infection in utero
A fetus can make igM and IgG shortly after birth. What is the caveat?
Only to proteins
What is the significance of having the half life of maternal antibodies waning after 1-3 months?
A window appears where the child is suceptible to infection because no longer protected by maternal antibodies
What is the benefit of administering conjugate vaccine to a mother during the 3rd trimester?
Allows for the mother to generate antibodies, protect the child for longer
How does herd immunity relate to vaccination for the entire population?
Means that the population can be protected without having to vaccinate everyone
What are the factors that influence the probability of disease transmission? (6)
Suceptible population # Contact frequency Duration of infection Agent stability in environment # of organisms for infection Super spreader
The major factor determining probabilty of infection is _
The number of suceptible individuals
Super spreaders usually have high organism load. What is their relative set point compared to controls?
Shifted down and right
What is immune escape? How can it be prevented?
Mutations confer resistant to strains of bacteria.
Use whole organism vaccines, increase chance some component is immunogenic
What component of the complement cascade does IgM use to initiate a response to polysaccharide antigen?
C1q
What component of the immune response is deficient in children under 2?
T-independent response, allows for response to polysaccharide antigens
An infants GI tract is protected by _
Maternal IgA from breastmilk
There are 4 assumptions of herd immunity theory. They are _
Closed population
Interactions are random
Anyone can get infected
Infection leads to immunity
What is the effect of vaccine on death rate following infection? How does vaccination reduce death rate?
It doesn’t change death rate after infection
It reduced # of people who die by reducing # of people who get infected
What is the meaning of endemic level? Hypoendemic level? Hyperendemic?
Endemic - Basal level in population
Hypo - lower than reference population
Hyper - Higher than reference population
