Vaccines Flashcards
What is adaptive immunity?
- Protection develops more slowly (days)
- Developed by individual only after specific challenge (antigen)
- Effective only against the specific antigen
- Has enhanced ability to deal with recurring antigen (memory)
What is innate immunity?
- Basic resistance to disease (immunity) that an individual is born with (innate)
- Immediate protection against microbes
- Response in place before foreign challenge (antigen) present
- Same response regardless of antigen (non-specific) or previous exposure (no memory)
What are the phases of adaptive immune responses?
1st exposure to antigen leads to development of a primary immune response with proliferation of activated B cells and T cells into effector cells and some to memory B cells and T cells
How is memory from adaptive immunity formed through vaccination programme?
1st exposure to antigen A memory –> 2nd exposure to antigen A produces higher AB concentration –> greater and faster immune response
Vaccine is what form of immunisation?
Active immunisation
Vaccines contain antigen that stimulate an immune response and result in immunologic memory
What is live (attentuated) vaccines?
A virus is weakened, often by repeatedly passing it through a tissue culture in which it replicates poorly
What is the advantages and disadvantages of (attentuated) vaccines?
+ Activates T cells
+ 1/2 doses can provide lifelong immunity
- Must be refrigerated
- Less safe for ppl with weakened immune system
Examples of live (attentuated) vaccines?
MMR
Varicella
Rotavirus
What are some precautions we need to take note for live vaccines?
- Avoid in preg women
- not given in infancy
- Avoid in severely immunocompromised pts –> Haematologic (blood cancer) /solid organ malignancies; Immunosuppressive meds; chemo; HIV with CD4 < 200
- Avoid giving another live vaccine within 28 days
- Spaced 3-10 months apart from adm of AB containing products e.g. immunoglobulins, blood transfusion
What is an inactivated vaccine?
- Whole, killed
- pathogen treated w heat/ chemicals to kill it before it is introduced into the body
What are the + and - of inactivated vaccines?
+ easy to store and transport
+ low risk of causing an infection
- elicits weaker immune response
- may require several doses and boosters
What are examples of inactivated vaccines?
Polio, Hep A, rabies
What is a subunit vaccine?
Portein or polysacc or conjugated
One or more parts of the pathogen, are isolated and used to evoke an immune response
What are the + and - of subunit vaccines?
+ low risk of adv rxn
+ used in ppl w weakened immune systems
- difficult to manufacture
- may require boosters
What are the examples of subunit vaccines?
Hep B, Influenza, pertussis, Pneumococcus
What are Toxoid vaccines?
Toxin produced by pathogen instead of he pathogen itself, is deactivated and used to produce the immune response