M27 - Vaccine Flashcards
what are the 2 types of natural immunity?
– Active - natural recovery from infection
– Passive - maternal antibodies
What are the 2 types of artificially acquired immunity?
– Vaccination (active immunisation)
– Passive immunisation
What is passive immunisation?
- Specific antibodies purified from blood of donor.
* Antibodies/immunoglobu lin injected into recipient
What are the advantages of passive immunisation?
immediate protection
What are the disadvantages of passive immunisation?
protecting short-lived
when is passive immunisation used?
When unprotected person has been exposed to infectious agent, and there is not sufficient time for the patient to develop own antibodies by active immunisation
what is a vaccination?
Administration of material of ‘microbial’ origin (vaccine) to a susceptible person to stimulate their immune defences
What does vaccination stimulate?
long lasting protection against a specific disease
When does immunological memory sometimes not work?
drugs, alcohol ,immunocompromised
what should an ideal vaccine do?
• Provide resistance to disease – (not necessarily to infection) • Protect for as long as possible • Be safe – minimal side effects • Be stable • Be cheap (especially 3rd world) • Be perceived as “good and effective”
What are the 4 types of vaccines?
- toxoid
- subunit
- Inactivated (killed)
- live-attenuated
Describe toxoids.
• Purified toxin treated with formaldehyde to
render it non-toxic without changing antigenicity
• Toxoids usually adsorbed onto adjuvents to
improve their stimulatory effect
• E.g. tetanus toxoid, diptheria toxoid
What does adjuvents do?
cause low grade inflammation to increase success of immune response
Describe subunit vaccines.
• Consist only of small portion of microbe - enough to stimulate immune response, not enough for infection
• No risk of infection
• Generally expensive
• Generally not very effective
• Conjugate vaccine;
– where subunit is attached to another protein
Describe inactivated vaccines.
- Microbe is exposed to denaturing agent or heat
- Aim is loss of infectivity without loss of antigenicity
- Little risk of vaccine associated infection
- Stable
- Not possible to achieve correct balance for all microbes
- Not always effective at stimulating correct immune response
Describe live attenuated vaccines.
• Microbe with reduced pathogenicity • Aim is to stimulate immune response without causing disease • Very good immunogens – (stimulate correct immune response) • Unstable • Risk of reversion to virulence
Describe the administration of live and killed vaccines.
Live- may be natural route or injection , may be single dose
Killed - injection, usually multiple doses
Is an adjuvant needed for live or killed vaccines?
Live- not required
killed- usually required
Describe the safety of live and killed vaccines.
live- may revert to virulence
killed- pain from injection
What is the cost of live and killed vaccines?
live- low
killed- high
what is the duration of live and killed vaccines?
live- usually years
killed- may be long or short
what is the immune response of live and killed vaccines?
live- IgG, IgA, cell-mediated
killed - mainly IgG, little or no cell-mediated
What are common side effects of vaccines?
swelling and redness at injection site, transient fever, malaise, headache
What are rare side effects of vaccines?
– anaphylactic shock
– have adrenalin and oxygen available
Name complications of vaccines.
• “live” material in “killed” vaccine preparation
• Allergic effects
– e.g. influenza virus is grown in eggs
• Toxicity
– e.g. typhoid vaccine
(vaccine contains large numbers of killed Salmonella typhi so large amounts of endotoxin)
who should live vaccines not be given to?
• Pregnant women -
unless significant risk of exposure outweighs risk to foetus
• Immunosuppressive treatment
– Individualsonhighdosesofsteroids – with malignant conditions -
• lymphomas, leukaemia;
• HIV +ve patients should not get BCG vaccine
what is herd immunity?
the level of disease resistance of a community or population
Describe how herd immunity works.
– Sufficient levels of immunised people to prevent circulation of disease & infection of non-immunised.
– Applies only to diseases that pass form person to person
– Ultimately herd immunity leads to eradication
Name factors effecting herd immunity.
– Environmental • Population density • Time of year – Immunestatus • HIV – Vurulence of disease • Measles highly infectious >90% protection required for herd immunity • Varies but 90% a common figure.
Describe measles.
- Highly contagious viral illness
- First described in 7th century
- Near universal infection of childhood in pre- vaccination era
- Frequent and often fatal in developing worlds
Name conditions caused by measles complications and 5 reported.
- Diarrhea (8%)
- Otitis media (7%)
- Pneumonia (6%)
- Encephalitis (0.1%)
- Hospitalization (18%)
- Death (0.2%)
Name adverse reaction from MMR.
- Fever
- Rash
- Joint symptoms
- Thrombocytopenia
- Parotitis
- Deafness
- Encephalopathy
Describe the vaccination paradox in the post factual era.
- Increased vaccine safety
- Increased vaccine coverage
- Decreased disease incidence
- Decreased doctors trust
- Decreased parents trust
Name some childhood vaccines.
- Meningitis C
- Rotavirus
- MMR
- Chickenpox
- BCG (TB)
- Flu
- HepB
What is human papilloma virus (HPV)?
• Cervical Cancer
– 1000UKdeathsperanum
• 18 Yrs (25%)
• 24 Yrs (40%)
• HPV types
– 16,18,
What has been in place since 2009 for HPV?
– Vaccination for 15-17Yrs
– Types 16 & 18 Protection
– Prevent 70% of cervical cancer cases
Name some adult vaccines.
- Flu Vaccine (65 years and older every year)
- Men ACWY (teenage and university)
- Pneumococcal (PPV) (65 years)
- Whopping Cough (Pertusis)
Give summary slide.
• Active & Passive immunisation • Ideal Vaccine & four types • Herd immunity • Contra-indications, side effects • Childhood vaccines – Diseasescontrolled, • Adult vaccines – Specific uses & targeted diseases • MMR & perception of vaccines
