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Back to Basics, 2013 POPULATION HEALTH : Immunization. Presented by N. Birkett, MD Epidemiology & Community Medicine. IMMUNIZATION (1). “ Discuss the population health benefits of immunization programs ”
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Back to Basics, 2013POPULATION HEALTH :Immunization Presented by N. Birkett, MD Epidemiology & Community Medicine
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
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.
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
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
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
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)
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
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
Human Papilloma Vaccine (HPV) (3) • Need three doses • 2nd dose: 2 months after 1st dose • 3rddose: 6 months after 1stdose • 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
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
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
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)
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
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 Guidegives more detailed information
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
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
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
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)
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!