Immunoprophylaxis Flashcards
ways of acquiring immunity
natural infection and vaccination
innate and adaptive effector mechanisms
read
effector antibodies
- bacteria toxins: neutralization
- bacteria in extracellular space: opsonization
- bacteria in plasma: complement activation -> lysis and phagocytosis
t-cell activation steps
- signal recognition: apc + mhc presents to t cell
- costimulation: b7 and cd 40 from apc, cd40L and cd28 from t cell
- proliferation
effector t cells
cd4 (th1 and th2) or cd8 (cytotoxic t cells)
functions of cd4 and cd8 cells
cd4: stimulate tregs, macrophages, b cells, and differentiation of cytotoxic t cells; promote migration and activation
cd8: induce target cells to die, produce protein in lytic granules, release cytokines
protein lytic granules produced by cd8 t cells
- perforin: polymerizes to form pore on target membrane
- granzymes: activate apoptosis in cytoplasm of target cell
- granulysin: induces apoptosis
primary antibody response to vaccine
- “priming”
- bridging of apcs
- days to weeks
- forms memory cell population for months, years, or life
secondary antibody response to vaccine
- “boosting”
- memory cells can make greater and more rapid response
primary vs secondary response
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types of vaccines
- live attenuated
- inactivated
- subunit
- toxoid
principles of live attenuated vaccines
- antigens are live and replication competent, but reduced virulence (similar to natural infection)
- unpredictable + safety and stability concerns
principles of inactivated vaccines
- dead or inactivated viruses
- may not always induce immune response, may not be long lived
- need several doses
- no risk inducing disease, more stable than lav
principles of reassortant vaccines
- at least 2 different strains of same pathogen
principles of subunit vaccines
- contain antigenic parts of pathogen
- con: needs exact details on which components to use
- no guarantee immune memory will be formed
- very safe
principles of protein based subunit vaccine
- uses specific isolatted protein of pathogen
- con: can be denatured
- acellular pertussis vaccine and hep b vaccine
principles of polysaccharide vaccine
- creates response against molecules in pathogen’s capsule
- small, not very immunogenic
- ineffective in infants and young children
- only short term immunity
principles of conjugate subunit vaccine
- create a response against molecules in a pathogen’s capsule
- long term protective response
- can prevent common bacterial infections
- hib and pneumococcal
polysaccharide vs polysaccharide conjugate vaccines
read
principles of toxoid vaccines
- based on toxin of bacteria (ex. tetanus or diptheria)
- harmless protein-based toxin as antigen
- aluminum or calcium salts = increase immune response
- no possibility of reversion and stable
adverse events following immunization
- vaccine product related reaction (inherent property)
- vaccine quality defect related reaction (+ administration device)
- immunization error-related reaction (handling, prescribing, or administration = PREVENTABLE)
- immunization anxiety related reaction
- coincidental event (non vaccine causes)
t/f combining antigens increases the risk of adverse reactions
false, does not increase
advantages of combination vaccines
- reduces cost of stocking and administering vaccines
- reduces cost of hc visit
- improving timelines
- addition of new vaccines into immunization programs
t/f routine childhood vaccination (except bcg) are not contraindicated in children with asymptomatic hiv infection
true
t/f symptomatic hiv/aids patients can take live attenuated vaccines
false
focus of covid vaccine candidates
spike protein and its variants
principles of mrna vaccines
- use nucleoside modified mrna
- ex: pfizer, biontech, moderna
- can be developed in labs using readily available materials
principles of adenovirus vector vaccines
- non-replicating viral vectors
- produce the antigen that elicits systemic immune response
- ex: astrazeneca, sputnik v, convidicea, j&j
safety monitoring for covid vaccine
- vaccine adverse event reporting system and v safe
common side effects of covid vaccine
- pain at injection site!!
- fatigue and headache
- fever
- resolve in a few days, responsive in paracetamol and nsaids, more common in younger
- second shot has more side effects
delayed reaction to covid vaccine
- occur within 5-14 d: warmth, pruritus over/near injection site, regional adenopathy (axillary)
- not a contraindication
- responsive to oral antihistamines and topical steroids
t/f anaphylaxis vs covid vaccine is common
false
t/f no evidence of causal relationship between covid vaccination and death
true
absolute contraindications to covid vaccine
- hypersensitivity to vaccine components
- severe allergic rxn (anaphylaxis) after previous mrna covid vaccine (other therapy not a contraindication)
