Immunisation and Prophylaxis Flashcards
When is immunisation currently recommended?
Childhood schedule
Special patient groups
Occupational
Travellers
When is prophylaxis recommended?
Travellers
Post-exposure
Post-exposure HIV
Surgical
How does active immunisation work?
Antigen stimulates the immune espouse which provides long-term immunity
Relies on immunological memory
Does active immunisation produce an immediate effect?
No immediate effect - but faster and better response to next antigenic encounter
Vaccine types
Live attenuated
Killed/inactivated
Detoxified exotoxin
Subunit
Examples of live attenuated vaccines
Measles Mumps Rubella Polio BCG Varicella Zoster virus Yellow fever Typhoid
How do live attenuated vaccines work?
Attenuation of pathogenic organism by repeated passage in cell culture or non-human host
Usually promotes a full long-lasting antibody response after one or two doses
Contraindications for live attenuated vaccines
Pregnancy
Immunocompromised
Why might the storage of live attenuated vaccines be difficult in developing countries?
They require refrigeration until administration
Examples of inactivated/killed whole cell vaccines
Pertussis Polio Influenza Hepatitis A Cholera Rabies Japanese encephalitis Tick borne encephalitis Smallpox
How do inactivated/killed whole cell vaccines work?
Pathogenic organism inactivated by chemical inactivation, usually with formaldehyde
Promote weaker immune responses in comparison to live vaccines
Possible side effects of inactivated vaccines
Inflammatory responses against other proteins and antigens contained within the vaccine
Examples of detoxified exotoxin vaccines
Tetanus
Diphtheria
How do detoxified exotoxin vaccines work?
Toxin treated with formalin
Toxoid retains the antigenicity but has no toxic activity
Only induces immunity against the toxin, not the organism that produces it
Examples of subunit vaccines
Pertussis - acellular Haemophilus influenzae type B Meningococcus groups A, C, W and Y Pneumococcus Hepatitis B Typhoid Anthrax
Benefits of subunit vaccines
Safe to use as there is no infectious agent and they are highly purified
Easy to produce large amounts
Disadvantage of subunit vaccines
Increased purity leads to loss of immunogenicity - may need an adjuvant
Example of recombinant vaccine
Hepatitis B surface antigen for HBV vaccination
How are recombinant vaccines prepared?
Gene encoding the antigen is excised from the organism’s nucleic acid, purified and mixed with plasmids
Gene is then inserted into yeast chromosome which grows in culture to produce the antigen
Immunisation schedule for 2 months old
Diphtheria Tetanus Bordetella pertussis Polio Haemophilus influenzae B Pneumococcal conjugate
Immunisation schedule for 3 months old
Diphtheria Tetanus Bordetella pertussis Haemophilus influenzae B Men C
Immunisation schedule for 4 months old
Diphtheria Tetanus Bordetella pertussis Haemophilus influenzae B Men C Pneumococcal conjugate
Immunisation schedule for 1 year old
Haemophilus influenzae B Men C MMR Pneumococcal conjugate Men B
Immunisation shcedule for 2, 3 and 4 years old
Influenza
Immunisation schedule for 3-5 years old
4-in-1 booster DTaP, IPV
MMR
Immunisation schedule for 12-13 year old girls
Human papilloma virus
Immunisation schedule for 14 years old
3-in-1 booster DT, IPV and men ACWY
What is herd immunity?
Vaccinated individuals less likely to be a source of infection to others
This reduces the risk of un-vaccinated individuals being exposed to infection
Individuals who cannot be vaccinated therefore still benefit from routine vaccination
At what age are infants vaccinated with the new rotavirus vaccine and what protection does it offer?
Babies at 2 and 3 months
90% protection
Immunisation recommended for special patient and occupational groups
BCG Influenza Pneumococcal Hepatitis B Varicella-zoster
Who is the BCG vaccination still given to?
Some infants (0-12 months) from areas of the UK with an annual incidence of 40 or more per 100,000 or with parents/grandparents born in a country with an annual incidence of TB of 40 or more per 100,000
Children screened at school for TB risk factors if appropriate
New immigrants, previously unvaccinated, from high prevalence countries
Contacts of respiratory TB patients
Healthcare workers
Example of the patient groups recommended to get the influenza vaccination
Nursing home residents Healthcare workers Immunodeficiency Immunosuppression Asplenia/hyposplenism Chronic liver, renal, cardiac or lung disease Diabetes mellitus Pregnant women Coeliac disease Age > 65
In what adult groups is pneumococcal polysaccharide vaccine recommended?
Immunosuppression Immunodeficiency Asplenism/hyposplenism Sickle cell disease Chronic liver, renal, cardiac or lung disease Diabetes mellitus Coeliac disease
In what patient groups is hepatitis B vaccination given?
Children at high risk of exposure to HBV Babies born to infected mothers Healthcare workers IVDA Men who have sex with men Prisoners Chronic liver or kidney disease
In what patient groups is varicella vaccination (chickenpox) given?
Patients who have a suppressed immune system
Children in contact with those at risk of severe VZV
Healthcare workers if sero-negative and in contact with patients
Dosage of varicella vaccine
Aged 1-12 years - 1 dose
Aged 13 or older - 2 doses, 4-8 weeks apart
In what patient group is the herpes zoster vaccination given?
All elderly patients, 70+
Use of human normal immunoglobulin
Contains antibodies against hepatitis A, rubella, measles
Used in immunoglobulin deficiencies
Treatment of some autoimmune disorders
Examples of disease-specific immunoglobulin
Hepatitis B Ig Rabies Ig Tetanus anti-toxin Ig Varicella Ig Diphtheria anti-toxin Botulinum anti-toxin
Examples of agents used in passive immunisation
Human normal immunoglobulin
Human specific immunoglobulin
Diphtheria anti-toxin
Tetanus anti-toxin
Examples of natural passive immunisation
Placental transfer of IgG Colostral transfer of IgA Human normal immunoglobulin Human specific immunoglobulin Disease-specific immunoglobulin
Examples of artificial passive immunisation
Treatment with immunoglobulin
Immune cells
Advantages of passive immunisation
Gives immediate protection
Disadvantages of passive immunisation
Short-term effect
Serum sickness
Graft vs host disease
Possible contraindications of vaccination
Febrile illness
Pregnancy
Allergy
Immunocompromised
Risk assessment of the traveller
Health of traveller Previous immunisation and prophylaxis Area to be visited Duration of visit Accommodation Activities Remote areas Recent outbreaks
General measures to be advised when travelling
Care with food/water Hand washing Sunburn/sunstroke Altitude RTAs Safe sex Mosquitoes
Common immunisation for travellers
Tetanus Polio Typhoid Hepatitis A Yellow fever Cholera
Immunisations for travellers in specialised circumstances
Meningococcus ACWY Rabies Diphtheria Japanese B encephalitis Tick borne encephalitis
Prophylaxis options
Chemoprophylaxis against malaria
Post-exposure prophylaxis
HIV post-exposure prophylaxis
Surgical antibiotic prophylaxis
ABCD of malaria prevention
A - awareness of risk
B - bite prevention
C - chemoprophylaxis
D - diagnosis and treatment
Bite prevention advice
Cover up at dawn and dusk
Insect repellent sprays/lotions
Mosquito coils
Permethrin-impregnated mosquito nets
Chemoprophylaxis for malaria
Malarone daily
Mefloquine weekly
Doxycycline daily
Chloroquine weekly and proquanil daily for vivax, ovale and malariae
Contraindications for mefloquine use
History of psychosis or epilepsy
Side effects of psychosis and nightmares
Malaria advice to travellers on return
Any illness occurring within 1 year, and especially within 3 months, of return might be malaria
Patients should seek medical attention if they become ill, particularly within the 3 months
