Principles of Immunisation Flashcards
Types opf immunity
- adaptive= active (immunisation vaccines, infection or
exposure) - innate= passive: recieved immunity (placental transfer of IgG, colostral transfer of IgA, immunoglobulin
therapy or immune cells)
Passive immunity
- short term immunity using antibodies produced outside the body
- specificity
- no memory
Active immunity
- the immunity that results from the production of antibodies by the immune system in response to the presence of an antigen
- specificity
- memory
Advantages of passive immunity
- Gives immediate protection
- A quick fix
Disadvantages of passive immunity
- Short term effect - no immunological memory
- Serum sickness - 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 natural and artificial examples of passive immunity
Natural: maternal immunoglobulins transferred to foetus or neonate naturally using a specialised mechanism involving the neonatal Fc receptor
Artificial:
* Snake bite - passive infusion of antibody specific for the toxin
* Hypogammaglobulinaemia (1/2ndry indsion of gamma-globulins to reduce infection
* Rabies immunoglobulin - “post-exposure prophylaxis” together with vaccination
Examples of natural and artificial, active immunity
- natural= exposure/infection
- artificial= vaccination
Advantages of active immunity
- Antigen (whole organism or part of it) stimulates immune response
- (often) Long term immunity - may be lifelong
- Immunological memory
- No immediate effect, but faster and better response to next antigenic encounter
Vaccination
administration of antigenic material (a vaccine) to stimulate an individual’s immune system to develop adaptive immunity to a pathogen
common diseases vaccinated against
probs don’t need to know
measles, mumps, rubella, polio, diptheria, tetanus, cholera, typhoid, yellow fever, HPV, shingles, hep A
Explain vaccines which kill the whole organism
- arget organism, e.g., polio virus is killedT
- Effective and relatively easy to manufacture
- Booster shots likely required
- Virus must be heat killed effectively - any live virus can result in vaccine-related disease
Explain vaccines that attenuate the whole organism
- An avirulent strain of target organism is isolated
- Can be very powerful and better than killed
- Simulate natural infection
- Reversion back to virulent form
- Refrigeration required
Give the mechanism of attenuation
- pathogenic virus is isolated from a patient and grown in human cultured cells
- cultured virus used to infect monkey cells
- virus acquires many mutations that allow it to grow well in monkey cells
- the virus no longer grows well in human cells (it is attenuated) and can be used as a vaccine
Types of vaccine
4 types
- Live attenuated (LAV)
- Inactivated (killed antigen)
- Toxoid (inactivated toxins)
- Subunit (purified antigen)
How does the subunit vaccine work
- Recombinant proteins
- Generally very safe
- Easy to standardise
- Not very immunogenic without an effective adjuvant
- Need to understand how to generate immunity
How does the toxoid vaccine work
- Toxin is treated with formalin
- Toxoid retains antigenicity but has no toxic activity
- Only induces immunity against the toxin, not the organism that produces it
- Can’t proliferate in environment???
ex inc: tetanus, diphtheria
Diseases LAV used for
*Tuberculosis (BCG)
*Oral polio vaccine (OPV)
*Measles
*Rotavirus
*Yellow fever
Diseases inactivated vaccines used for
*Whole-cell pertussis (wP)
*Inactivated polio virus (IPV)
what diseases are toxoid vaccines used for
*Tetanus Toxoid (TT)
*Diphtheria toxoid
Diseases subunit vaccines used for
*Acellular pertussis (aP)
*Haemophilus influenzae type B (Hib)
*Pneumococcal (PCV-7, PCV-10, PCV-13)
*Hepatitis B (hepB)
Vaccine schedule for children
- 2 months old= Diphtheria, tetanus, pertussis, polio, Haemophilis influenzae type b, Streptococcus pneumoniae, rotavirus
- 3 months old= Diphtheria, tetanus, pertussis, polio, Haemophilis influenzae type b, Neisseria meningitidis C, rotavirus
- 4 months old= Diphtheria, tetanus, pertussis, polio, Haemophilis influenzae type b, Streptococcus pneumoniae
- 12-13 months old= Haemophilis influenzae type b, Neisseria meningitidis C, measles, mumps, rubella, Streptococcus pneumoniae
- 2/3/4 years old= Influenza
- > 3 years 4 months old= Diphtheria, tetanus, pertussis, polio, measles, mumps, rubella
- 12-13 years old= Human papilloma virus (females only)
- 13-18 years old= Diphtheria, tetanus, polio, Neisseria meningitidis C
vaccines for travellers
- Hepatitis A
- Typhoid
- Neisseria meningitidis serogroups A, C, W135, Y
- Cholera
- Yellow fever
- Japanese encephalitis
- Tick-borne encephalitis
- Rabies
Contraindications of vaccination
reason for someone not to recieve treatment (harmful)
Temporary:
* Febrile illness
* pregnancy - cannot be given live attenuated vaccines
Permanent:
* allergy
* immunocompromised - cannot be given live attenuated vaccines as individuals may develop disease from the vaccine strain
Explain herd immunity
- Primary aim (of vaccination) is to protect individual who recieves the vaccination
- Vaccinated person less likely to be source of infection to others
- Dec risk of unvaccinated individual being exposed
- Individuals who can’t be vaccinated still benifit
