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Back to Basics, 2014POPULATION 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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Some recent news storiesMeasles cases in Ottawa and BC

• non-immunized children have been suspended from school for two weeks

• Measles is communicable 4 days BEFORE a child shows the illness– Easy to spread cases to non-immunized children

– Easy to start an epidemic if immunization rates are low

• Measles is not a trivial disease– 1-2 weeks of missed school

– moderate discomfort

– 1 in 20 develop pneumonia

– 1 in 10 develop ear infections • can lead to permanent hearing loss

– 1/1,000 develop encephalitis

– 1/1,000 will die

– Can lead to miscarriage or premature birth in a pregnant woman.

03/2014

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Some recent news storiesStudents suspended over immunizations.

• Almost 1,000 of Ottawa’s high school students have been suspended for

improperly-kept immunization records.

• About 900 students have been sent home for 20 days for not having the

records, not necessarily for not having their shots.

Dropping immunization rates

• Alberta's immunization rates are continuing to drop, worrying some doctors

Vaccine-related adverse event rates found to be low in Ontario ...

• A new Ontario report on vaccine safety shows the rate of adverse events

reported after vaccinations in the province is low.

• 56 serious vaccine-related adverse events reported in 2012, in a year when

7.8 million vaccinations took place– convulsions, seizures and anaphylaxis,

– No fatalities03/2014

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Side Effects of Vaccine (DTaP/IPV/Hib)

• DTaP/IPV/HIB vaccine– Serious adverse effects are rare– Most common adverse reactions

• redness, swelling, pain at injection site

– fever and irritability are less common– redness and swelling greater than 3.5 cm with

minimal pain• more common in children receiving fifth consecutive dose

at 4 to 6 years of age• reported in 16% of children

– in older people receiving Td booster• injection site reactions in 10% of people

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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.03/2014

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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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C-13

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Abbreviation Target(s) Type

DTaP-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)• Gardasil

– 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

1703/2014

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

• even if patient has 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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Toxoid; active & passive agents

• Tetanus is caused by a toxin secreted by the infectious organism (Clostridium

tetani).– Immunizing agents are directed against the toxin

– Active immunization is called a 'toxoid'.

• For tetanus (and hepatitis B)– Can administer the passive and active agents at the same time

– Inactivated antigen in the toxoid does not react with the circulating antibody).

• Do NOT administer a passive agent along with an active, live attenuated virus

vaccine (e.g. MMR and measles passive immunization).– The antibody interacts with the attenuated organism and prevents it from dividing.

– Blunts or eliminates the immune response.

– Wait at least 3 months before giving the active agents in such a case.

• http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/genrec.pdf

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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 regions• 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 – May be required for some countries

– 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 more protective

• Anaphylaxis– Need to differentiate from fainting

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IMMUNIZATION (5)• Neurological damage

– Often a major worry of parents• BUT: there is no evidence that MMR causes autism

– Research claiming a link has been debunked as fraudulent• Dr. Wakefield was convinced he would win a Nobel Prize, even

though he falsified medical records and recruited patients unethically (for example, drawing blood from children at a birthday party) in a bid to "prove" the theory. [BMJ, 2011]

• The British Medical Journal revealed in Thursday's edition that the disgraced researcher had planned to sell diagnostic tests for the invented condition, and estimated his company would reap $112-million a year. He stood to bring in another $43-million annually for a measles vaccine he invented to replace MMR.

– Casual rather than causal relationship

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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)– Not a 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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