Transcript Document

VACCINES & IMMUNISATION
Dr. I. M. Gemmill
Medical Officer of Health
KFL&A Public Health
Kingston, Canada
Associate Professor
Department of Community Health & Epidemiology
Department of Family Medicine, Queen’s University
Hosted by Paul Webber
[email protected]
www.webbertraining.com
A Webber Training Teleclass
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
OBJECTIVES
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To describe the value of vaccines in reducing the morbidity
and mortality from communicable diseases
To describe the various types of vaccines, desirable
qualities in a vaccine, their components and how they work
To describe correct storage, handling, administration and
documentation of immunisation
To describe the nature of side effects of vaccines and to
distinguish between real and alleged side effects
To communicate effectively with vaccine recipients and
their parents about the benefits and risks of vaccines
To outline reputable and disreputable sources of
information on immunisation
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
COST BENEFIT OF VACCINE
‘Vaccination programmes are considered to be the most costbeneficial health intervention and one of the few that
systematically demonstrate far more benefits than costs.’
Intervention
Cost per Life Year Saved
MMR vaccine for children :
Mammography > 50 :
Smoking cessation advice (> 1 ppd) :
Low cholesterol diet (men >20, >180 mg/dl) :
< 0$
810$
9800$
360.000$
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
POLIO INCIDENCE 1949-1995
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
DIPHTHERIA CASES 1924-1995
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
TETANUS DEATHS 1924-1995
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
MEASLES INCIDENCE 1924-1995
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
RUBELLA CASES 1924-1995
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
IMPACT OF VACCINES ON
COMMUNICABLE DISEASES IN CANADA
DISEASE
Before vaccine*
2001
Diphtheria
9000
0
Polio
20.000
0
Measles
300.000
33
Rubella
69.000
23
*Number of cases in an outbreak year
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
TYPES OF IMMUNISATION
Active immunisation:
 the formation of antibodies in response to an antigenic
stimulus
 protection tends to be long-term
Passive immunisation:
 the administration of preformed antibody, from a
human or animal source, to provide short-term
protection against disease
 e.g. gamma globulin, specific immune globulin
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
QUALITIES OF A GOOD VACCINE
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Effective
 immunogenicity:
 induces antibodies in individuals
 efficacy
 reduces disease in populations
 duration of protection:
 need for boosters is limited
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
QUALITIES OF A GOOD VACCINE
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Safe
 common side effects are mild
 serious side effects are rare
 does not cause disease
 not transmissible to others
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
QUALITIES OF A GOOD VACCINE
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Ease of administration
 injectable
 needle
 jet injector
 nasal spray
 oral
 edible
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
QUALITIES OF A GOOD VACCINE
 Stability
Freezer stable
 Fridge stable
 Stable at room temperature
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I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
QUALITIES OF A GOOD VACCINE
 Cost
Older vaccines cost a few dollars per
dose
 Newer vaccines enter the market at
60$ per dose or higher
 Competition brings the price down
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I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
HOW DO VACCINES WORK?
Vaccines cause the immune system to
provide protection against disease
without causing disease
They stimulate an immune response to
provide protective antibodies, memory
cells, or both
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
NEW VACCINE DEVELOPMENT
Vaccines go through a number of processes:
 Bench research
 Animal trials
 Clinical trials for safety & efficacy
 Licensure
 National expert recommendations
 Field use: private pay or provincial
programme
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINES MANUFACTURING
Vaccines are among the most rigorously controlled
medical products:
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Production & purification of the desired antigen
Inactivation or disruption
Sterilisation
Packaging & preservatives
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
TYPES OF VACCINES
Live vaccines:
 measles, mumps, rubella
 varicella
 yellow fever
 oral polio vaccine (Sabin)
 BCG
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
TYPES OF VACCINES
Killed vaccines, whole cell:
 polio
 rabies
 hepatitis A
Killed vaccines, particles:
 pertussis
 influenza
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
TYPES OF VACCINES
Killed vaccines, polysaccharide:
 meningococcal
 pneumococcal
Killed vaccines, conjugated:
 meningococcal
 pneumococcal
 haemophilus influenzae
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
TYPES OF VACCINES
With live vaccines, a small amount of vaccine virus is
administered
The vaccine virus replicates, thereby mimicking the disease
process more closely
The protection that they provide is generally therefore longerlasting and requires fewer total doses
The fact that live virus replicates in this process means that
these vaccines have special precautions :
 Pregnancy
 People whose immune status is compromised
 Cold chain must be respected
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
TYPES OF VACCINES
With vaccines that are not live, the total dose
administered is all that the immune system has to
work with
Some vaccines therefore have adjuvants or protein
carriers to make them more immunogenic
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
COMPONENTS OF VACCINES
Vaccines contain:
 Antigens to induce an immune response
Vaccines may also contain:
 Adjuvant: aluminium hydroxide
 Preservatives: thimerosal
 Antibiotics: neomycin
 Other stabilisers: albumin
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE INDICATIONS
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Indications for use are based on epidemiological
risk
May be for universal use e.g. pertussis
May be for targeted populations e.g. travel,
lifestyle
May be for pre-exposure (routine) use
May be for post-exposure (outbreak control) use
e.g. hepatitis A
Refer to national expert statements for indications,
rather than product monographs
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE SCHEDULES
Every vaccine has a schedule of administration
The schedule is determined by clinical trial design
and post-marketing research
The product monograph is a legal document
providing the most conservative approach to
vaccine use
Recommendations of expert bodies are the most
valid sources for reference for vaccine use
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE SCHEDULES
Some vaccines have more flexible schedules than
others :
 hepatitis B vaccine vs. conjugated
pneumococcal
Schedules need to accommodate the requirements
and precautions for all vaccines that are
recommended e.g. timing of live virus vaccines
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
IMMUNE MEMORY AND THE NEED FOR
BOOSTERS
There are two ways in which vaccines protect:
 Antibodies are produced that may last for years
 Memory cells may be produced, that create
antibodies quickly in response to an antigenic
challenge
 We judge vaccines by antibody, but they may
protect through the second mechanism
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
IMMUNE MEMORY AND THE NEED FOR
BOOSTERS
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Some vaccines need only one dose for lasting
protection
 Conjugated meningococcal vaccine in adults
Most vaccines need more than one dose to be fully
effective
Some vaccines need regular boosting throughout
life
 Toxoids: tetanus & diphtheria
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
IMMUNE MEMORY AND THE NEED FOR
BOOSTERS
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Live virus vaccines may need less doses in general
because they mimic the disease process better
Oral polio requires more than one dose because
one of the three types predominates with ease dose
Some vaccines just work incredibly well after two
or three doses
 hepatitis A, inactivated polio
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE ADMINISTRATION
There are several ways to administer vaccines:
 IM
 SC (usually live virus vaccines)
 Oral
 ID
The route of administration is specific to each vaccine.
It is essential to check and be sure of the route of
administration for a given vaccine.
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE ADMINISTRATION
Technique:
 Use the right-sized needle (e.g. 1 inch for adult
I.M.)
 Deltoid for adults and older children
 Anterolateral surface of the thigh for infants and
young children
 No gluteal injections
 Sharp needles only
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE ADMINISTRATION
Technique:
 Cleanse the area with alcohol and let it evaporate
 Separate needle and syringe for each injection
 Aspirate
 Practise doing it quickly, so that patients are less
uncomfortable
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE TIPS
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Prophylactic use of antipyretics may decrease
minor side effects
Interruption of the recommended schedule does
not usually mean restarting (exception:
conjugated pneumococcal)
Giving a vaccine after too short an interval is a
problem
Recommended vaccine dosage should NEVER be
reduced
Prematurity does not affect vaccines schedules
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
STORAGE & COLD CHAIN
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The storage requirements may vary from vaccine to
vaccine
Storage requirements must be respected
Some vaccines can undergo one insult without loss but no
insult to the vaccine is preferred
Live virus vaccines are generally more susceptible to insult
that others
The prime example is fridge failure
In general, most vaccines are kept at 2 to 8° C
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
IMMUNISATION RECORDS
Every immunisation event should be recorded on the
patient’s chart and a record provided to the
vaccinee
Immunisations are reportable in some provinces
Provincial systems vary from province to province
but are not connected
There is currently no national system to keep track of
immunisations
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE SAFETY MONITORING
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Vaccines are probably the best monitored of all medical
interventions
The process of licensing vaccines is rigorous (average 2
years)
There is a requirement to report possible AVEs in most
provinces
Companies conduct post-marketing surveillance
Immunisation Monitoring Programme ACTive (IMPACT)
Advisory Committee on Causality Assessment (ACCA)
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE CONTRAINDICATIONS
The only true contraindication to any vaccine
is a previous anaphlylactic reaction or
severe hypersensitivity to any component of
the vaccine.
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE CONTRAINDICATIONS
Contraindications to live virus vaccines:
 Pregnancy:
 although no birth defect has ever been
recorded
 may have to balance risk versus benefit e.g.
Yellow Fever vaccine
 Some immunodeficiency states
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE SIDE EFFECTS
SIDE EFFECTS INCLUDE:
 Local (at the injection site):
 Swelling, induration, tenderness, erythema
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Systemic (examples):
 Fever, rash, arthralgia, myalgia,
 Severe: anaphylaxis, GBS
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE SIDE EFFECTS
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Common side effects are generally milder
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Serious side effects are generally rare
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Side effects may vary from vaccine to vaccine,
based on the components
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Some side effects are simply owing to the
injection
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE SIDE EFFECTS
Every medical intervention has risks
 Vaccines are no exception
 Patients must be informed about risks and
side effects
 Informed consent for immunisation is a
requirement
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I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE SIDE EFFECTS
CONDITIONS THAT ARE NOT DUE TO VACCINES:
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Chronic fatigue syndrome (hepatitis B vaccine)
Multiple sclerosis (hepatitis B vaccine)
Autism (MMR vaccine, vaccines containing thimerosal)
Ulcerative colitis (MMR vaccine)
Brain damage (pertussis vaccine)
SIDS (many vaccines)
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE PRECAUTIONS
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There are precautions for giving any medical
intervention, including vaccines
Precautions are specific to the vaccine
Example:
 Live virus vaccines must be given at the same
time or with an interval of at least 28 days
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINES IN PREGNANCY
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Live virus vaccines are contraindicated in pregnancy
because of the theoretical risk of congenital anomaly
Inadvertent immunisation of a pregnant woman with a live
virus vaccine should be reported for monitoring purposes
Other vaccines may be used safely in pregnancy
Risk versus benefit must be considered
Some vaccines are indicated in pregnancy :
 influenza
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINE RISK VERSUS BENEFIT
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Every vaccine as some small risk attached to it
The benefit of vaccine normally far outweighs any risk
Sometimes, it is better to respect even a theoretical risk e.g.
live virus vaccine in pregnancy
Example: YF vaccine in immunocompromised travellers
If the risk outweighs the benefit, vaccine should not be
administered e.g. smallpox vaccine
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
COMMUNICATING RISK VERSUS BENEFIT
The advice of a health professional is the most important
factor in whether a person receives a vaccine
Clear, simple, concise information must be provided about
both the risks and the benefits of vaccines (CMPA policy
on pneumococcal & meningococcal vaccines)
Some people may need more detailed explanations than
others
Public health and professional bodies can help
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
MYTHS ABOUT VACCINES
Common myths about vaccines:
 Vaccines don’t really work
 Vaccines aren’t safe
 We don’t need vaccines because the diseases are rare
 There are too many antigens given to children now
 Vaccines weaken the immune system
 A healthy lifestyle is all one needs to prevent infection
 There is an industry conspiracy to poison children for
profit
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
ANTI-VACCINATIONISTS
There is a small group of zealots who are opposed to vaccine
They believe that vaccines are unsafe and subscribe to
conspiracy theories about them
They are willing to spread untruths about vaccines publicly
They may cause damage to public programmes :
 hepatitis B in Manitoba, France
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
ANTI-VACCINATIONISTS
There are many books published and web sites
maintained by the anti-vaccine faction
Many have respectable names and purport to
be authoritative
Some are supported by health
paraprofessionals
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
ANTI-VACCINATIONISTS
Web sites to check
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Vaccine Risk Awareness Network
http://64.41.99.118/vran/membership/contact_us.htm
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National Vaccine Information Centre
http://www.909shot.com/
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Children of God for Life
http://www.cogforlife.org/
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Dr. Joseph Mercola
http://www.mercola.com/article/vaccines/death.htm
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
RELIABLE VACCINE WEB SITES
Web sites to check :
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Canadian Public Health Association
http://www.immunize.cpha.ca/english/links.htm
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Public Health Agency of Canada
http://www.phac-aspc.gc.ca/dirddimr/immunization_e.html
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United Kingdom Department of Health
http://www.immunisation.nhs.uk/
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
RELIABLE VACCINE WEB SITES
Web sites to check :
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World Health Organisation
http://www.who.int/vaccines/
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Centres for Disease Control & Prevention
http://www.cdc.gov/nip/
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINES ARE NOT JUST FOR KIDS
People have the impression that vaccines are
primarily for children
While vaccines do prevent disease in children, there
are many vaccines that adults need:
 Routine : tetanus, diphtheria, pertussis
 Lifestyle : hepatitis A & B
 Travel : YF, typhoid, hepatitis A, etc.
I. M. GEMMILL, MD, CCFP, FRCP(C)
IMMUNISATION
VACCINES ARE NOT JUST FOR KIDS
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Other occupations :
 Health care provider : hepatitis B, MMR, influenza
 Vets : rabies. hepatitis A
 Zookeepers: hepatitis A vaccine
 Staff of some institutions: hepatitis A & B
 Prison guards : hepatitis B
 Lab workers : many vaccines
 Military : many including anthrax, plague
I. M. GEMMILL, MD, CCFP, FRCP(C)
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