Vaccines Flashcards
What is immunisation?
The process of rendering a person immune or resistant to an infectious disease.
It can be done naturally or artificially (through vaccinations).
What is a vaccination?
It is a process of stimulating a persons protective adaptive immunity against a microbe through exposure to its non-pathogenic forms (vaccines).
What are vaccines?
Vaccines are live attenueated or killed organisms or microbial components given for the prevention of an infectious disease.
They can also be given as a form of treatment, post-exposure prophylaxis, after a person may have been exposed to a pathogen.
What are the two types of immunisation?
Active and passive.
What are the two types of active immunisation, and what are the benefits?
Natural - where the person is exposed to the pathogen.
Artificial - vaccination.
This confers long-term immunity, due to the activation of the innate immune response and the formation of memory cells.
What are the two types of passive immunisation, and what do they confer?
Natural - antibodies transferred through breast milk or the placenta during pregnancy.
Artificial - antibodies given as therapy.
There is short-term protection as no memory cells have been stimulated to be synthesised.
What is the impact of vaccination?
It decreases the effect that a disease will have on a person - they will have fewer or no symptoms.
It decreases the prevalence and incidence of a disease, with the aim to eradicate the disease.
What are the types of vaccine?
Live attenuated virus/ bacteria - this is where the pathogen retains the ability to replicate and grow, requiring an immune response (but does not usually cause an illness).
Inactivated virus/ toxins - this is where the pathogen or a component of a pathogen is unable to replicate and cause harm, but still stimulates an immune response.
What are the advantages and disadvantages of live attenuated vaccines?
Advantages:
- They require one or few doses.
- They reproduce natural infection.
- High level of protection.
Disadvantages:
- They can only be given to certain people (immunocompromised patients cannot receive).
- They can mutate back to their wild-type and cause disease.
- Storage issues.
What are the advantages and disadvantages to inactivated vaccines?
Advantages:
- They are safe.
- They can be given to a larger population.
- They are stable and won’t mutate.
Disadvantages:
- They can confer different immunity between different people.
- They may require a large number of doses.
- Less effective than live attenuated vaccines.
What is the target populations for a vaccine?
Infants - greater than 8 weeks old.
Children - between the age of 12 and 14.
Adults - greater than the age of 65.
There can be any ages with certain underlying conditions.
What are the 3 routes of vaccine administration?
Oral - this is given when it mimics the route of the normal organism. Done with rotavirus.
Nasal - this is done with influenza and is good for children and those scared of needles.
Injectable - this is done with most vaccines. It can be intramuscular (deltoid or anterolateral leg in infants), subcutaneous, or intradermal.
How do vaccinations confer immunity?
The antigenic material with adjuvants (enhancers) are introduced to a patient.
The antigenic material is identified and processed by antigen presenting cells.
It is then presented to CD4/ CD8 cells to initiate an innate immune response.
Effector cells are synthesised to remove the antigenic material and CD8+ memory cells and memory B cells remain.
What are the goals of active immunisation?
To confer immunity to the patients receiving the vaccine to produce a quicker and more competent response.
Herd immunity.
What is herd immunity?
Herd immunity is the process of conferring immunity to a large proportion of a population to help protect a minority of a population that cannot be exposed to the pathogen.
It can be through vaccination or natural infection (much less effective).
