Flashcards in Immunisation Deck (19):
- Prevent individual disease
(life-long, not just in children)
- Ideally, halt carriage & transmission
-> herd immunity is a side effect
- Ideally, eliminate > eradicate disease
- High coverage is operational target
Given an example of passive immunity.
Immunoglobulin (Ig), which contains antibodies pooled together from the blood of many donors, can be injected into a person who needs antibodies. e.g. for Hep B
What is the drawback of passive immunity?
This type of passive immunity, although effective, usually disappears within several weeks or months.
What is active immunity?
Long-lasting immunity produced by the immune system in response to antigens.
What is the persistence of protection for many years after natural infection or vaccination called?
Which is the first antibody to be produced in an immune response?
Which antibody is responsible for the secondary immune response?
What happens when an antigen binds non-specifically to the variable region of an antibody?
Clonal expansion is triggered -> 1st wave of IgM production followed by IgG production.
What is the function of IgG?
Binds tightly to antigen. Simultaneous complement binding facilitates the destruction of the invader.
What are the advantages of live vaccines?
- Single dose often sufficient to induce long-lasting immunity
- Strong immune response evoked
- Local and systemic immunity produced
What are the disadvantages of live vaccines?
- Potential to revert to virulence
- Contraindicated in immunosuppressed patients
- Interference by viruses or vaccines and passive antibody
- Poor stability
- Potential for contamination
What are the advantages of inactivated/killed vaccines?
- Constituents clearly defined
- Unable to cause the infection
What are the disadvantages of inactivated/killed vaccines?
- Need several doses
- Local reactions common
- Adjuvant needed
- keeps vaccine at injection site
- activates antigen presenting cells
- Shorter lasting immunity
What types of local reactions are possible with vaccines?
Pain, swelling or redness at injection site; small nodules may form at injection site
What types of general reactions are possible with vaccines?
Fever, irritability, malaise, fatigue, headache, nausea, vomiting, diarrhoea, loss of appetite
What happens to the frequency of reactions with live vaccines?
Freq of reactions decreases with no of doses - ab produced in response to live vaccine neutralises the small amount of vaccine virus in subsequent vaccine dose.
What happens to the frequency of reactions with inactivated/killed vaccines?
Freq of reactions increases with no of doses - if ab levels are good from earlier vaccination, ab binds to the vaccine antigen in a subsequent dose leading to inflammatory response.
How long after inoculation would you see a reaction with a killed/inactivated vaccine?
Generally within 48hrs following vaccination