Immunisation Flashcards
What is the primary prevention of disease?
Prevent on sent of disease pre exposure: Childhood immunisation Routine vaccines for elderly Travel vaccines Occupational vaccines High risk clinical groups
What is secondary prevention?
Alter course of infection/disease to prevent or limit consequences:
Immunoglobulin - hep B, rabies, varicella zoster
How do vaccines work?
Teach the immune system to recognise bacteria and viruses before the individual encounters them as potential pathogens so allowing the body to fight against the pathogens
What are the immunological mechanisms in vaccinations?
Active immunity
Passive immunity
Herd immunity
What is an antigen?
Parts of bacteria and viruses which are recognised by the immune system
Antigens are usually proteins or polysaccharides (sugars)
Immune system generates a response to antigens often by the production of antibodies
What is an antibody?
Proteins which binds to antigens
Antibodies are very specific to individual antigens
When an antibody-antigen complex is formed, this alerts other immune cells (lymphocytes: B and T cells)
What is a B cell (humoral immune response)?
Triggered to produce antibodies when encountered with a foreign antigen
Where are B cells produced?
Bone marrow
Where are T cells produced?
Thymus
What are the different types of T cells and what do they do?
CD4+ and CD8_
Orchestrate the response of the immune system by binding to other cells and sending out signals
How is passive immunity transferred from mother to baby?
Via placenta
Lasts up to one year
Some antigens e.g. measles can pass through but others such as pertissus cannot
How can passive immunity be transferred from another person or animal?
Antibodies from blood donors
Human normal Ig
Specific Ig
What human Ig can be given via passive immunity?
Hep B
Rabies
Varicella zoster
What anti-toxin can be given via passive immunity?
Diphtheria
Botulinum
What are the advantages to passive immunity?
Rapid action Post-exposure Can attenuate illness Outbreak control Can be used if contraindication to active vaccination
What are the disadvantages to passive immunity?
Short term protection Short term window Blood derived Hypersensitivity reaction Expensive
What is a live virus vaccine and what are examples of live viruses?
Attenuated organism, replicates in host
OPV, measles, mumps, rubella, varicella, rotavirus, flut
What are the different subtypes of inactivated vaccines?
Suspensions of killed organisms
Subunit vaccines
Conjugate vaccines
What are examples of suspensions of killed organisms vaccines?
Whole cell pertussis
Whole cell typhoid
What are examples of subunit vaccines?
Toxoids - diphtheria toxoid, tetanus toxoid, pertussis toxoid
Polysaccharides - pneumococcal, typhoid
What are examples of conjugate vaccines?
Polysaccharide attached to immunogenic proteins e.g Hib MenC
What are contraindications to vaccines?
Confirmed anaphylaxis
Egg allergy - flu and yellow fever
Severe latex allergy
Acute or evolving illness - defer till resolved/stabilised
What are specific contraindications to live vaccines?
Immunosuppression (primary, radiotherapy, high dose steroids, HIV)
What is herd immunity?
Protect unvaccinated individuals, through having sufficiently large proportion of population vaccinated
Vaccinated individuals stop transmission of organism
What percentage of the population need to be vaccinated to provide herd immunity for measles?
90%
What percentage of the population need to be vaccinated to provide herd immunity for mumps?
75-86%
What percentage of the population need to be vaccinated to provide herd immunity for smallpox?
80-85%
What is the purpose of the routine vaccine schedule?
To provide early protection against infections that are most dangerous for the very young - whooping cough, pneumococcal, Hib, meningococcal
To ensure continued protection by providing subsequent immunisations and booster doses before reaching age when risk increase
How is the age chosen when to give certain vaccines?
Based on age-specific risk of disease, risk of complications and ability to respond to the vaccine
optimal age chosen for scheduling children may be a compromise between risk of disease and level of protection
Currently in scotland, what diseases are offered vaccination from?
Diphtheria Rotavirus Meningococcal Hib Hepatitis B Measles Mumps Rubella HPV - cervical cancer Flu Pneumococcal Polio Tetanus Whooping cough
What is the hexavalent vaccine?
Diphtheria Tetanus Pertussis Polio Haemophilus infleunza type b Hepatitis B
What vaccines are given at 2 months?
Pneumococcal, hexavalent,meningococcal group B, rotavirus
What vaccines are given at 3 months?
Hexavalent
Rotavirus
What vaccines are given at 4 months?
Hexavalent
MenB
Pneumococcal
What vaccines are given at 12-13 months?
MenB
Pneumococcal
Hib/MenC
MMR
What vaccines are given at 3 years 4months - 5 years?
MMR
Diphtheria, tetanus, pertussis and polio booster
What vaccine is given between 2-12 years?
Flu
What vaccine is given to girls in S1 and S2?
2 doses of HPV
What vaccine is given between 13-14 years?
Tetanus, diphtheria and polio booster
Meningococcal groups A, C, W and Y
What are the selective childhood vaccines for children in at-risk groups?
Flu (annual) aged 2 or older
Pneumococcal polysaccharide vaccine aged 2 or older
bCG up to 16
Hep B all ages
What adult vaccine programmes are available?
Pneumococcal polysaccharide vaccine - 65 years old
Shingles - 70 years old
Seasonal flu - over 65s, at-risk groups, pregnant women
Hep B
Travel
Occupational
What is a public health notification?
Legal duty of medical practitioners to notify health board on clinical suspicion of specified diseases or a health risk state posing significant public health risk
Notification in writing with in 3 days
Notification by phone as soon as reasonably practicable if urgent
What diseases are to be registered by medical practitioners based on reasonable clinical suspicion and should not await lab confirmation?
Anthrax Botulism Brucellosis Cholera E.coli O157 infection Diphtheria HUS Hib Measles Meningococcal disease Mumps Necrotizing fasciitis Paratyphoid Pertussis Plague Poliomyelitis Rabies Rubella SARS Smalpox Tetanus TB Tularemia Typhoid Vrial haemorrhagic fevers West nile fever Yellow fever
What is the presentation os diphtheria?
URTI characterised by sore throat, low rade fever
White adherent membrane on tonsils, pharynx and/or nasal cavity
What causes diphtheria?
Aerobic gram positive bacterium - corynebacterium diphtheriae
What causes meningococcal disease?
Invasive infection due to neisseria meningitidis
What different infections can meningococcal disease cause?
Meningitis
Septicaemia
Men and sept
How is meningococcal disease spread?
Person to person contact through respiratory droplets of infected people
Colonisation of nasopharynx common, important reservoir for disease
What is the incubation period of meningococcal?
3-5 days
What is the peak ages in meningococcal disease?
Less than 5 years
15-24 years
How are new vaccines investigated?
Phase 1 = is it safe, is it immunogenic
Phase 2 = how reactogenic is it, what dose should be used, how does it compare with current vaccines
Phase 3 - is it efficacious, are there any rare reactions/ safety issues
What is the yellow card scheme?
Passive reporting
Suspected adverse drug reactions
What does the uptake of vaccines depend on?
Perception of relative risks and benefits
What is the definition of control of a disease?
Reduction of the disease to a locally acceptable level; continued intervention required to maintain reduction e.g. diarrhoeal disease
What is the definition of elimination of a disease?
Reduction to zero incidence of specified disease in defined geographical areas; continued intervention measures required e.g. neonatal tetanus
What is the definitino of elimination of infections?
Reduction to zero incidence of infection caused by a specific agent in a defined geographical area/ continued measures to prevent re-establishment of transmission required e.g. measles, polio
What is the definition of eradication of a disease?
Permanent reduction to zero fo the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts; intervention measures are no longer needed e.g. smallpox, rinderperst
What is extinction of a disease?
The specific infectious agent no longer exists in nature of in the lab. There are no examples of this
