Immunization

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Immunization
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Introduction

• At beginning of 20th century, communicable
  diseases were a major cause of death
• Development of effective vaccines and
  immunizations programs has dramatically altered
  previous patterns of disease in humans

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• Routine childhood immunization begins at 2 mo. of
  age ends at 14-16 yr.
• Monitoring immunization rates in school aged
  populations important preventive strategy

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• Immunization rates of 90 or higher are required
  to prevent outbreaks of disease
• 1979, Britain 100,00 cases of pertussis 36
  deaths after drop in immunization rates

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• Ireland, 2000 1,200 cases of measles after
  immunization rates fell to 76 only 148 cases in
  1999

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Vaccine Preventable Diseases

• Diphtheria
• National Goal Eliminate indigenous diphtheria
  (by 1997)
• Organism corynebacterium diphtheria
• Toxin producing

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• Transmission direct contact
• Symptoms
• Membrane formation on pharynx, nose, etc.
• Complications
• Degeneration of peripheral nerves cardiac
  muscle
• 5 - 10 case fatality rate

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• Pertussis
• National goal Better control of pertussis with
  new adult vaccine
• Organism Bordatella pertussis
• Transmission Direct contact with respiratory
  secretions

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• Symptoms
• Increasing cough progressing to severe paroxysms
  followed by inspiratory whoop
• Subsides over a period of weeks
• Low grade fever

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• Complications
• Bronchopneumonia
• Encephalopathy
• Morbidity mortality highest in infancy
• 1400 infants dies from pneumonia or brain damage

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• Tetanus
• Organism clostridium tetani
• Transmission introduction of spores by
  contamination of wound with soil or feces

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• Complications
• Weight loss
• Bone fracture
• Case fatality rate of 10 - 20

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• Symptoms
• Muscle rigidity spasm
• Primarily masseter neck muscles
• Secondarily trunk muscles
• Late opisthotonus
• Body arches backward until the heels nearly touch
  the head

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• Polio
• Global Goal Eradication of polio
• Eradicated in Western Hemisphere in 1994
• Organism poliovirus (genus enterovirus) types 1,
  2 and 3

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• Transmission
• fecal-oral
• Contaminated food or water

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• Symptoms
• Fever
• Sore throat
• Muscle aches
• Drowsiness
• Headache
• GI symptoms

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• 90 asymptomatic
• 4 - 8 minor illness of a few days
• 1 - 5 viral meningitis
• 1 flaccid paralysis
• Complications
• Paralysis
• Death
• Post polio syndrome

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• Haemophilus Influenzae Invasive Disease
• Organism Haemophilus Influenzae Type b
• Transmission
• Direct person to person
• Oral
• Sneezing, coughing

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• Symptoms
• Sudden onset
• Fever
• Vomiting
• Lethargy
• Meningeal irritation often leading to stupor or
  coma

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• Complications
• Otitis media
• Epiglottitis
• Occult febrile bacteremia
• Cellulitis pneumonia
• With treatment, death occurs in 120 cases
• 13 survivors have detectable brain damage

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• Decline in epiglottitis r/t introduction of Hib
  vaccine in 1992

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• Measles
• National Goal Eliminate indigenous measles by
  2005
• Organism measles virus
• Transmission
• Droplet spread
• Direct contact with nasal or throat secretions

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• Symptoms
• Fever
• Conjunctivitis
• Cough
• Rash

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• Complications
• Otitis media
• Pneumonia
• Encephalitis 11000 cases
• Complications more common in infants and adults
• Case fatality rate 2-3/1000 cases
• Can be up to 30 in developing countries

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• Mumps
• Organism mumps virus
• Transmission
• Droplet
• Direct contact with nasal or throat secretions

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• Symptoms
• Fever
• Aches
• Swelling of salivary glands
• Sometimes asymptomatic in children

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• Complications
• Encephalitis (1-2/10,000 cases)
• Deafness
• Orchitis (20 -30 of postpubertal males)
• Sterility rare
• Case fatality 1/10,000 cases

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• Rubella
• National Goal Eliminate indigenous rubella (by
  2000)
• Organism rubella virus
• Transmission
• Direct droplet
• Congenital via placenta

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• Symptoms
• Fever
• Rash
• Joint pain
• Lymphademopathy
• Conjunctivitis

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• Congenital rubella syndrome (CRS)
• LBW
• Cataracts, glaucoma, blindness
• Deafness
• Malformations
• Cardiac
• Hepatitis
• Chronic pneumonia
• Diabetes
• Hypothyroidism
• CNS defects

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• Complications
• Severe joint pain
• Thrombocytopenia
• Encephalitis

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• Hepatitis B
• National Goal Reduce prevalence of indigenous
  HepB by 90 by 2015
• Organism Hepatitis B virus

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• Transmission
• Sexual
• Perinatal
• Percutaneous
• Carriers
• 75 - 95 of exposed newborns will become carriers
• 30 unknown transmission

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• Symptoms
• Adults
• Nausea
• Vomiting
• Anorexia
• Rash
• Jaundice
• Asymptomatic in children

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• Complications
• Chronic hepatitis
• Cirrhosis
• Liver failure
• Liver cancer

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• Varicella (Chicken Pox)
• Organism varicella zoster virus
• Transmission
• Direct contact
• Airborne
• Household transmission amongst susceptible
  contact high

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• Symptoms
• Slight fever
• Mild constitutional symptoms
• Skin eruption
• Macropapular for a few hours
• Vesicular for 3-4 days
• Lesions occur in successive crops

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• Complications
• Viral or bacterial pneumonia
• Hemorrhagic complications
• Encephalitis
• Congenital varicella syndrome
• Children with acute leukemia at greatest risk for
  complications

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• Meningococcus Serotype C
• Organism Neisseria Meningitidis, serotype C
• One of several serotypes which circulate in
  populations on an irregular basis
• Groups A, B, Y also circulate in North America

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• Symptoms
• Sudden onset of fever
• Intense headache
• Nausea vomiting
• Stiff neck
• Petechial rash
• Transmission
• Direct contact
• Delerium coma

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• Case fatality rate is 9 - 12

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• Carrier prevalence of 25
• Complications
• Death
• Amputations (5)
• Neurological deficits
• Skin scars (12)
• Hearing loss (2)
• Renal problems (1)

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• Pneumococcal Pneumonia
• Transmission
• Droplet spread
• Direct oral contact
• Indirect contact with contaminated articles

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• Organism streptococcus pneumoniae
• 80 strains
• 90 of all pneumonias caused by 23 strains

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• Symptoms
• Sudden onset
• Fever
• Chest pain
• Dyspnea
• Productive cough
• Ear infection

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• Complications
• Pneumonia bacteremia
• Meningitis
• Death occurs in infants elderly

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• Influenza
• Organism Influenza A, B, or C
• Transmission
• Direct contact with respiratory secretions
• Direct contact with recently contaminated articles

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• Symptoms
• Sudden onset
• Fever
• Chills
• Headache
• Malaise
• Myalgia
• Cough
• Recovery 10 - 14 days

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• Complications
• Pneumonia
• Bronchitis
• Worsening of pre-existing chronic illnesses
• Death

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Immunity A Brief Review

• Active Immunity
• Long lasting immunity conferred by development of
  antibodies
• 2 types
• 1) Active conferred by active disease
• 2) Active conferred by vaccines toxoids

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• Passive Immunity
• Short term immunity produced by provision of
  ready-made antibodies (made by someone else)
• Two types

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• 1) Natural passive
• Conferred by mother to fetus by placental
  transfer of specific antibodies
• Mother must have active immunity to do this
• No natural passive immunity to pertussis

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• 2) Artificial passive
• Conferred by injection of specific types of
  antibodies
• Human immune serum globulin
• Specific human immune serum globulin
• Animal antiserum or antitoxin

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• Agents Conferring Active Artificial Immunity
• 1. Toxoids
• Bacterial toxins which have been heat or chemical
  treated to decrease virulence without destroying
  ability to stimulate antibody production

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• 2. Vaccines
• Suspension of attenuated or killed organisms
• Several forms
• Live attenuated bacteria or virus
• Killed bacteria or virus

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• 3. Adjuvants
• Substances added to immunizing agent to enhance
  antigenic effect
• Often work by slowing down absorption from
  injection site to increase length of time immune
  system is in contact with the antigens

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• 4. Fluid Toxoids Vaccines
• No adjuvants
• Produce a rapid secondary response
• Used when person has received initial
  immunization, but requires boosting of antibodies
• For example, tetanus toxoid given after a tetanus
  prone injury

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Scheduling Immunizing Agents

• 1. Primary Response to Antigens
• First response
• May be slow result in small concentrations of
  antibodies

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• 2. Secondary Response
• Faster and higher production of antibodies if
  body recognizes the antigen
• Interrupted immunization schedules can be picked
  up where they were left off,
• Not necessary to start over

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• 3. Boosters
• If primary response to a vaccine is sufficient,
  only 1 dose is needed
• If primary response not sufficient, boosters are
  needed to produce maintain antibody levels

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• Those immunized against specific diseases can
  actually experience a booster effect in response
  to the organism circulating in the environment
• Benefits of this type of boosting must be weighed
  against risks
• E.G rubella, use of live polio vaccine

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• 4. Herd Immunity
• Protective of vulnerable individuals
• 80 immunization rates limits ability of
  organisms to circulate in the population

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• Age of initiation of immunization based on 3
  considerations
• 1) Age at which passive immunity from mother is
  lost
• 2) Age at which communicable diseases pose a real
  risk to the infant
• 3) Age at which infants immune system is capable
  of an adequate immune response

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• Next 3 slides were immunization schedules

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Safety When Immunizing

• 1. Anticipating Adverse Effects
• Potential for anaphylactic shock
• Being prepared
• Distinguishing anaphylaxis from syncope
• See pp. 12-18 of Canadian Immunization Guide

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• Client assessment selection
• Contraindications are rare
• See pp. 4-7 of Immunization Guide

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• Immunization Guide provides instructions re
• Immunizing pregnant breastfeeding women (pp.
  18-19)
• Immunizing children with neurologic disorders (p.
  20)
• Immunizing immunocompromised individuals (pp.
  20-29)
• Immunizing premature infants (pp. 31-32)

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• Settings
• Better practice to immunize where there are
  others who can assist if emergencies arise

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• 2. Maintaining Proper Storage Conditions
• Maintaining the cold chain
• Fridges
• Transporting
• See p. 33, 35-37 of Canadian Immunization Guide

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• 3. Safe Disposal of Vaccines Needles
• Not as simple as when working in an institutional
  setting

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Issues in Immunization Programs

• 1. Compulsion
• Is it ever acceptable to compel that all
  individuals be immunized?
• If so, what onus does that pub on the health care
  system?

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Manitoba Childhood Immunizations Complete for Age
() 2003
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• 2. Consent
• Guidelines for informed consent on pp. 42-54

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• 3. Liability
• Good of the many outweighs the good of the few?
• Who compensates those injured by vaccines
• Vaccine safety monitoring
• See pp. 10-12 of Canadian Immunization Guide