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Back to Basics, 2013POPULATION HEALTH :

Immunization

Presented by N. Birkett, MDEpidemiology & Community

Medicine

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IMMUNIZATION (1)• “Discuss the population health benefits of immunization

programs”• Probability of contracting communicable disease depends on

probability that contacts are already immune, are carriers or have the disease

• If sufficient proportion of population is immune, then disease will not spread (herd immunity)

• Prevention is usually cheaper and more effective than treatment (if treatment even exists)

• Possibility of eradicating some diseases• Implications for school attendance (Ontario)

– Mandatory choice vs. mandatory immunization– Exclusion from school for non-immunized children during outbreak

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Side Effects of Vaccine (DTaP/IPV/Hib)

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Pertussis: Incidence trends 1924-2010

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Impact of drop in Vaccination rates

In Japan, pertussis vaccine coverage dropped from 90% to less than 40% because of public concern over two infant deaths that followed DPT immunization. Prior to the drop in coverage there were 200 to 400 cases of pertussis each year in Japan. From 1976 to 1979, following the marked drop in vaccine coverage, there were 13,000 cases of pertussis, of which over 100 were fatal.

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Standard immunizationsAge 0-17

• Diphtheria• Tetanus• Pertussis• Polio• H. influenzae B• Mumps• Measles

• Rubella• Hepatitis B• Chickenpox (varicella)• Pneumococcus• Meningococcus • Influenza• HPV

Taken from: Canadian Immunization Guide, 2010

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Abbreviation Target(s) TypeDTaP-IPV(pediatric)

DiphtheriaTetanusAcellular PertussisInactivated Polio

ToxoidToxoidacellularInactive, viral

Hib Haemophilus influenzae type b Conjugate

MMR MeaslesMumpsRubella

live, attenuatedlive, attenuatedlive, attenuated

Var Varicella live, attenuated

HB Hepatitis B recombinant

Pneu-C-7Pneu-C-13

Pneumococcal Conjugate

Men-C Meningococcal Conjugate

Tdap (adult)-lower dose of diphtheria

TetanusDiphtheriaAcellular Pertussis

ToxoidToxoidacellular

HPV Human Papilloma virus recombinant

Inf Influenza inactivate OR live, attenuated

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Pneumococcal vaccines (1)• 1,200 cases of pneumococcal pneumonia and meningitis in

Ontario, 2009– 4% case fatality rate

Prevnar 13• 13 valent pneumococcal conjugate vaccine to protect under age 6

years• Replaced Prevnar (7 valent) due to emergence of 3, 7F and 19A as frequently

reported serotypes• 19A is becoming resistant to first line antibiotics• Conjugated with diphtheria toxoid but does not protect against diphtheria

– Introduced fall 2010– Routine doses at 2, 4, 12 months of age

• 4 doses at 2, 4, 6 and 15 months if baby has a chronic disease

– At 12 months, child receives Prevnar 13, Meningococcal C conjugate and MMR vaccines

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Pneumococcal vaccines (2)Pneumococcal polysaccharide 23 valent vaccine

– Anyone age 2 or older with chronic conditions• moderate-severe respiratory, cardiac, cirrhosis, renal, diabetes,

asplenia, sickle-cell, CSF leak, immune deficiency, cochlear implant recipients

• U.S. adding– any asthma and cigarette smoking

• Booster dose 3-5 years later– Age 65 years or older

• everyone– Residents of nursing homes and chronic care facilities

• everyone– 50-80% effectiveness among the immunocompetent

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Meningococcal vaccines• Meningococcal C Conjugate Vaccine

• Give one dose at 12 months• May be offered in Grade 7 or age 14-16 for those

unimmunized• Meningococcal ACYW-134 Quadrivalent

Conjugate Vaccine• 2-55 years

• asplenic, complement, properdin or factor D deficiency, or cochlear implant recipient

• Meningococcal ACYW-135 Quadrivalent Polysaccharide Vaccine• Over 55 years for same indications as (2)

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Human Papilloma Vaccine (HPV) (1)• Garadsil

– Protects against 4 strains of HPV• Types 16 and 18 (linked to 70% of cervical cancer and 80% of anal

cancer)• Types 6 and 11 (linked to 90% of anogenital warts)

– Females age 9-45• Cervical, vulvar and vaginal cancer and precursor lesions• Cervical adenocarcinoma in situ• Genital warts

– Males age 9-26• Anogenital warts and general HPV infection

– Males and females age 9-26• Anal cancer and anal intraepithelial neoplasia

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Human Papilloma Vaccine (HPV) (2)• Ceravix

– Protects against 2 strains of HPV• Types 16 and 18 (linked to 70% of cervical cancer and 80% of

anal cancer)

– Females age 10-25• CIN Type 1, 2 and 3• Cervical adenocarcinoma in situ

• If goal is to protect only against type 16/18, can use either vaccine

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Human Papilloma Vaccine (HPV) (3)• Need three doses

– 2nd dose: 2 months after 1st dose– 3rd dose: 6 months after 1st dose

• Best to give prior to sexual activity– 40% of women become infected with HPV within 16 months after initiation

of sexual activity

• Ontario– Provided free to grade 8 girls in school

• Can still be given• once sexually active,• with previous pap abnormalities• have had a previous HPV infection

• Routine vaccination of boys would be useful

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Passive Immunization (1)• Direct administration of Immunoglobins against

specific organism– Human or animal origin for Ig’s– human derived agents are preferred to reduce side

effects (serum sickness)• Use

– exposure to organism prior to vaccination– people with compromised immune systems

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Passive Immunization (2)• Indications

– Measles (give within 3 days post-exposure)– Hepatitis A– Rubella

• supress symptoms• doesn’t prevent infection• Don’t use in pregnant women

• Not the primary method to deal with these diseases

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Passive Immunization (3)• Other available passive agents

– Botulism (equine)– Diphtheria (equine)– Hepatitis B (human)– Rabies (human)– Palivizumab for RSV (humanized monoclonal)– Tetanus anti-toxin– Varicella

• Not routinely available– require special orders– Check with Public Health Department (especially for Rabies)

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IMMUNIZATION (2)

• “State that a lapse in immunization schedule does not require re-instituting the initial series, merely giving it at the next visit”

• You can give a dose too early; you cannot give a dose too late

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IMMUNIZATION (3)• “Communicate to patients and parents about vaccine

benefits and risks”• Obtain an immunization history on all children• Late immunization is still very effective• Immigrants require special attention

– Depends on availability of good records; countries have different immunization coverage

– When in doubt, start the series again; – Canadian Immunization Guide gives more detailed

information

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IMMUNIZATION (4)• Travel

– Update regular immunizations– High risk exposure consider additional immunizations

• BCG, cholera, hepatitis A, typhoid, rabies– Meningococcal quadrivalent vaccine

• meningitis belt and Hajj– Influenza if the right season– Follow legal requirements

• Yellow fever (strict)• Cholera

– some countries may require; – medical exemption letter can be provided

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IMMUNIZATION (5)• “List possible complications of immunization”

• Seizures– secondary to fever– Introduction of acellular pertussis reduced febrile seizures dramatically and

was much more protective• Anaphylaxis

– Need to differentiate from fainting• Neurological damage

– Often a major worry of parents– BUT: rarely associated– Casual rather than causal relationship

• no good evidence for MMR causing autism

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IMMUNIZATION (6)• Rubella vaccination and adult women

– vaccine is ‘live, attenuated’– rubella infection during first trimester can cause spontaneous abortion,

serious fetal development problems, etc.• Congenital Rubella Syndrome (CRS)

– giving vaccine to pregnant women might, in theory, cause similar issues– NO EVIDENCE to support this risk– Inadvertent vaccine administration to pregnant women is NOT reason

for pregnancy termination– But as a general guidelines

• avoid immunizing women who might be pregnant• delay pregnancy at least 4 weeks post-immunization

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IMMUNIZATION (7)• “Discuss misconceptions about immunization

contraindications”

• Following are not contraindications:– Mild/moderate local reactions to previous dose– Mild acute illness with or without fever– Taking antibiotics– Allergy to penicillin, duck, molds, pollens– Positive Mantoux TB skin test– Breast feeding– Asplenia– Prior febrile seizure reaction (consider prophylactic acetaminophen)

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IMMUNIZATION (8)• “Discuss immunization of immuno-compromised children (e.g.,

asplenia, chronic diseases or seizures)”

• Asplenia (surgical or congenital/functional)– No contraindication to any vaccine– Particularly need protection against encapsulated bacteria to which these

individuals are highly susceptible. • Streptococcus pneumoniae, Haemophilus influenzae B, Neisseria meningitidis (A,C,Y,

W135),

• Immunosuppression– Avoid live vaccines– Follow regular immunization schedule– High dose steroids can mute immune response

• Congenital immunodeficiency– Read the Canadian Immunization Guide!

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