Principles of Immunisation Flashcards
What % of infant mortality under the age of 5 is vaccine preventable?
17%
Name the two subdivisions of immunity.
Innate and adaptive.
Name the two subdivisions of adaptive immunity.
Active and passive.
What type of immunity doesn’t change?
Innate immuinity.
What is the active immune system responsible for?
Memory and specificity.
What are the typical cells of adaptive immuinity?
Lymphocytes- both T and B.
Name two types of active immuinity.
Infection or exposure.
Immunisation vaccinations.
Name two types of passive immuinity.
Placental transfer of IgG
Colostral transfer of IgA
Immunoglobulin therapy or Immune cells
In passive immunity, what part of your body doesn’t have to do any work?
Your immune system.
What type of immunity doesn’t have an immune memory?
Passive immuinity.
Name the advatnages of passive immuinyt.
Quick response and gives immediate protection.
Name the advantages of passive immunity.
Quick response and gives immediate protection.
Name the disadvantages of passive immunity.
-No immunological memory so short term effect.
-Serum sickness as incoming antibody is recognised as a foreign antigen by the recipient and results in anaphylaxis
-Graft versus host disease (cell grafts only) – incoming immune cells reject the recipient
Give an example of natural passive immuinity.
Maternal immunoglobulins can be transferred to the foetus or neonate naturally using a specialised mechanism involving the neonatal Fc receptor
Given an example of artificial passive immunity.
1.Snake or spider bites, scorpion or fish stings - passive infusion of antibody specific for the toxin
2.Rabies Immunoglobulin -“Post-exposure prophylaxis” together with vaccination
For active immunity, what part is artificial and what part in natural?
Artificial= vaccination
Natural=exposure/infection
List some features of acitve immuinity.
-Antigen (whole organism or part of it) stimulates immune response
- Long term immunity – may be lifelong
-Immunological memory
-No immediate effect, but faster and better response to next antigenic encounter
Define vaccination.
Vaccination is the administration of antigenic material (a vaccine) to stimulate an individual’s immune system to develop adaptive immunity to a pathogen
Name some viruses we vaccinate against.
Measles, mumps, rubella.
Name the three types of vaccine.
Killed, attenuated and sub-unit.
Describe killed vaccines.
Target organism is killed.
Name some advantages of killed vaccines.
Effective and relatively easy to manufacture
Name some disadvantages of killed vaccines.
Booster shots likely required
Virus must be heat killed effectively – any live virus can result in vaccine-related disease
Describe attenuated vaccines.
An avirulent strain of target organism is isolated
Name some advantages of attenuated vaccines.
Can be very powerful and better than killed.
Simulates natural infection.
Name some disadvantages of attenuated vaccines.
Reversion back to virulent form
Refrigeration required
How do you generate a weakened form of a virus for a vaccine using attenuation mechanism.
- Pathogenic virus is isolated and gown in human cultured cells.
- These cells are grown on a different cell line and infect them e.g. in monkeys
- Virus acquires many mutations which allows it to grow well in this new type of cell.
- Virus no longer grows well in human cells so can be used in vaccines.
Name some advantages of the subunit vaccine involving recombinant proteins.
Generally very safe
Easy to standardise
Name some disadvantages of the subunit vaccine involving recombinant proteins.
Not very immunogenic without an effective adjuvant
Need to understand how to generate immunity
Describe toxin vaccinations.
Uses toxoids to develop a immune response against toxins.
Give an example of a virus treated w a killing vaccine.
Inactivated polio virus.
Give an example of a virus treated w a live attenuated vaccine.
Measles, yellow fever, tb.
Give an example of a virus treated w a subunit vaccine.
Hepetitis B
Give an example of a virus treated w a subunit vaccine.
Hepatitis B
Give an example of a virus treated w a toxoid vaccine.
Tetanus Toxoid (TT).
Name some vaccines you may need before travelling abroad.
Yellow fever, Hepatitis A, Rabies.
Name three vaccines you need to get boosters for until the age of 18.
Diphtheria, tetanus and polio
List some temporary factors which may prevent you from being able to get a vaccine.
Pregnancy, febrile illness (having or showing the symptoms of a fever)
List some permanent factors which may prevent you from being able to get a vaccine.
Allergies to vaccine
Those who are immunocompromised – cannot be given live attenuated vaccines as individuals may develop disease from the vaccine strain
What is the primary aim of a vaccination?
To protect the individual having the vaccine from a virus.
Name a secondary impact of having a vaccine.
Creating herd immunity.
Why does herd immunity reduce risks of a virus?
Vaccinated individuals are less likely to be a source of infection to others
Name a benefit of herd immunity.
Those who cannot get vaccinated still have a level of protection.
What makes a good vaccine?
- Strong/potent antibody response – high antibody titers
- Potent CD8+ cytotoxic T cell response->will kill affected cells
- CD4+ T helper response
- Memory
What cells optimise antibody production?
T cells
Which two groups of people is there most concern around?
Very old and very young
List some challenges facing the production of vaccines.
- Cannot get immunity from all infectious diseases e.g. malaria, flu
- Vaccines do not give lifelong protection.
- Generation of memory cells
- Protection for the very young and very old and immunocompromised groups.
- Antigenic shift and drift, and strain diversity in general
- Cold chain network
Why is flu very dangerous?
There are many different strains.
Every year there is a flu vaccine but it is never the same one.
What type of genome does flu have?
RNA genome
How many RNA stands does the influenza virus have?
8
Where does antigenic drift arise from?
Point mutations
What is the purpose of the cold chain network?
Maintain product quality from the time of manufacture until the point of administration by ensuring that vaccines are stored and transported within WHO-recommended temperature ranges.
Why are the very young vulnerable when it comes to vaccines?
-Short term antibody production
-Vulnerability <18–24 months to encapsulated (covered in polysaccharides). bacteria such as pneumococcus, Hib and meningococcus
-Immune systems haven’t had time to develop.
-Fewer FDC (cells which show the immune system presence of infection), and B cells do not express costimulatory molecules.
Why are the very old vulnerable when it comes to vaccines?
-Reduced efficacy or responsiveness to vaccination
-Oligoclonal responses lacking specificity
-Reduced plasma cell survival niches
What is the difference between a B cell and a plasma cell?
A B cell is what is stimulated by a viral pathogen and will then undergo development such that it changes aspects of its cell phenotype and basically becomes an antibody producing factory.
Plasma cells are antibody producing factory cells.
What are checkpoint inhibitors?
Powerful anti-tumour responses
Name a disadvantage of checkpoint inhibitors.
Can have immune related adverse effects
