Presented by: Date: Location:

1. Childhood vaccines at work in Canada Presented by:Date:Location:

2. Presentation overview The case for immunization Vaccine safetyVaccines in CanadaMyths, facts and commonly asked questionsPublic policyResources © 2010 Canadian Paediatric Society I www.cps.ca

3. Sources of information Based on Your Child’s Best Shot: A parent’s guide to vaccination (3rd edition, 2006)For updates including position statements from the CPS Infectious Diseases and Immunization Committee and current information for parents, visit the CPS websites: www.cps.ca and www.caringforkids.cps.ca Reviewed by the CPS Infectious Diseases and Immunization Committee. Lead reviewers: Dr. Bob Bartolussi and Dr. Dorothy Moore. © 2010 Canadian Paediatric Society I www.cps.ca

4. The case for immunization © 2010 Canadian Paediatric Society I www.cps.ca

5. Why we immunize • Vaccines save lives: A public health success story • Vaccines are safe and effective: The diseases they prevent can cause permanent disability or even death • It’s a small world: Travel can spread rare diseases quickly • Many vaccine-preventable diseases have no effective treatments • For some diseases, like tetanus, infection does not produce immunity: Vaccines produce immunity … Last, but not least … © 2010 Canadian Paediatric Society I www.cps.ca

6. …Vaccines protect everyone • Directly: the person vaccinated, and • Indirectly: people who are vulnerable to disease, eg.,babies, children, the elderly, people with a weak immune system • Vaccines keep communities healthier: children in school, parents working, people interacting normally © 2010 Canadian Paediatric Society I www.cps.ca

7. How vaccines work Immunology 101 • Bacteria and viruses have unique proteins and polysaccharides (complex sugars) on their surfaces called antigens • Immune system targets antigens using antibodies and lymphocytes • Lymphocytes (a type of white blood cell): include B-cells, T-cells and memory cells • Memory cells enable the immune system to recognize germs it has seen before, creating immune memory © 2010 Canadian Paediatric Society I www.cps.ca

8. Immunity • Long-lasting immunity depends on memory cells.Immune memory is the ability the immune system acquires to identify the presence of a germ and destroy it • Two ways to achieve immunity: Natural infection or immunization • – Natural infection causes illness and can lead to complications, • permanent damage, even death • – Vaccines protect without causing severe illness © 2010 Canadian Paediatric Society I www.cps.ca

9. Immunology of vaccines Types of vaccines © 2010 Canadian Paediatric Society I www.cps.ca

10. Vaccine success in Canada © 2010 Canadian Paediatric Society I www.cps.ca

11. Vaccine success in Canada (cont’d) © 2010 Canadian Paediatric Society I www.cps.ca

12. Risks and benefits of vaccines © 2010 Canadian Paediatric Society I www.cps.ca

13. Risks and benefits of vaccines (cont’d) © 2010 Canadian Paediatric Society I www.cps.ca

14. Vaccine success stories • Smallpox has been eradicated. No cases anywhere in the world since 1979. Children are no longer vaccinated against smallpox • Paralytic polio eliminated from most of the world. Today, endemic in only four countries: Afghanistan, India, Nigeria, Pakistan – Cases dropped from 350,000 in 1988 to 1606 in 2009 – Recent outbreaks in former Soviet republics of Tajikistan, Uzbekistan – Tocompletely eradicate polio, all children must be vaccinated © 2010 Canadian Paediatric Society I www.cps.ca

15. Why we (still) immunize • When vaccination rates decline, rates of disease increase • Example: In the late 1980s, former Soviet Union states saw vaccine supplies disrupted, collapse of their public health system and socioeconomic instability • Result: decrease in childhood immunization rates • Diphtheria epidemic followed: more than 150,000 cases and more than 4,000 deaths in the newly independent and Baltic states • Mass vaccination program eventually controlled the epidemic • Lesson: Complacency can be fatal © 2010 Canadian Paediatric Society I www.cps.ca

16. Why outbreaks (still) occur • Outbreaks occur for different reasons, such as: • Public doubt: In the early 2000s, a flawed autism/MMR study in the U.K. led to decline in measles vaccination • – Results: Increase in local measles infection rates and deaths, and • spread of measles to other countries • – Lesson: Vaccination must continue to prevent disease outbreaks • Travel: Measles and mumps have been introduced into Canada by travellers, causing local outbreaks • 2008: Polio spread by travellers from the 4 countries where it remains endemic to 20 others • – Lesson: It’s a small world! Travel can spread a rare disease very • quickly © 2010 Canadian Paediatric Society I www.cps.ca

17. Why outbreaks (still) occur (cont’d) • Waning immunity: Large mumps outbreak in 2007-08. Started in Nova Scotia, spread to New Brunswick and Alberta, with sporadic cases elsewhere • Mainly affected 20 to 29-year-olds in school settings • Prompted recommendation for a second dose of vaccine for high school, college/university students who had received only one dose in early childhood • Lesson: There may be a need for a second “booster” dose of mumps vaccine © 2010 Canadian Paediatric Society I www.cps.ca

18. Vaccine safety © 2010 Canadian Paediatric Society I www.cps.ca

19. How vaccines are approved for use in Canada • The Biologics and Genetic Therapies Directorate (BGTD), Health Canada, reviews and approves all vaccines for human use in Canada • To be approved, vaccine providers must meet acceptable standards of safety, quality (efficacy) • Production: All aspects of production are supervised by the BGTD • Safety: BGTD does independent lab testing to evaluate safety and efficacy of early batches of vaccine • Quality: Specified by the BGTD, and repeatedly tested by lot sampling before and after vaccine is released for sale © 2010 Canadian Paediatric Society I www.cps.ca

20. Recommendations for vaccine use • NACI: National Advisory Committee on Immunization makes recommendations to the Chief Public Health Officer • CIC: Canadian Immunization Committee assesses NACI recommendations and advises on operational plans • Provinces/territories use NACI and CIC recommendations to develop immunization programs • NACI’s Canadian Immunization Guide: Web-based guidelines from the Public Health Agency of Canada,published every 4 years (most recent edition 2010), at www.phac-aspc.gc.ca • Canadian Paediatric Society: Infectious Diseases and Immunization Committee’s position statements, at www.cps.ca © 2010 Canadian Paediatric Society I www.cps.ca

21. Monitoring vaccine safety • Adverse events: Health effects occurring after immunization that may or may not be related to the vaccine • Mild adverse events, such as fever and swelling at the injection site, are common. More serious reactions are rare • Post-marketing surveillance of adverse events: The system for reporting and reviewing adverse events once a vaccine has been approved for use • Information gets to the Public Health Agency of Canada through doctors and nurses reporting to health officials • Doctors and nurses providing vaccines should know the local procedure for reporting vaccine adverse events to public health © 2010 Canadian Paediatric Society I www.cps.ca

22. Entities involved in monitoring vaccine safety • Canadian Adverse Events Following Immunizations Surveillance System (CAEFISS): Receives reports fromdoctors, nurses • Advisory Committee on Causality Assessment (ACCA): Reviews all reported cases of serious adverse events • IMPACT: Immunization Monitoring Program, ACTive • The Vaccine Adverse Event Reporting System (VAERS): Post-marketing safety surveillance program in the U.S. • Institute of Medicine (IOM, U.S.): Immunization Safety Review Committee • GACVS (WHO): Global Advisory Committee on Vaccine Safety © 2010 Canadian Paediatric Society I www.cps.ca

23. Vaccines in Canada © 2010 Canadian Paediatric Society I www.cps.ca

24. Routine childhood vaccines • Pneumococcal vaccine: Protects against bacterial infections caused by Streptococcuspneumoniae,including meningitis, pneumonia, and ear infections • Meningococcal vaccine: Protects against bacterial infections caused by Neisseria meningitidis, including meningitis and septicemia, a serious blood infection • HPV vaccine: Protects against human papillomavirus types that cause cervical/vaginal cancer and genital warts • Rotavirus vaccine: Prevents rotavirus diarrhea • 5-in-1 (DTaP-IPV-Hib): Protects against diphtheria, tetanus, pertussis, polio, and bacterial infections caused by Hib (Haemophilus influenzae type b), including meningitis (a brain infection), and other serious infections • MMR: Protects against measles, mumps, and rubella • Hepatitis B vaccine • Varicella (chickenpox) vaccine • Seasonal influenza (“flu”) vaccine • Tdap: Tetanus, diphtheria and pertussis booster for teens and adults © 2010 Canadian Paediatric Society I www.cps.ca

25. Additional vaccines or a “catch-up” schedule • Children with certain chronic conditions or who travel outside of North America may require additional vaccines • Children new to Canada may not have received vaccines which are routine here • Children who move within Canada may miss a dose of vaccine because schedules are not uniform across the country © 2010 Canadian Paediatric Society I www.cps.ca

26. Contraindications to vaccination • Anaphylactic or other serious allergic reaction after receiving a vaccine is a contraindication to further doses of that vaccine • People with certain immune system disorders should not be given live vaccines (eg., measles, mumps, rubella, varicella, oral typhoid) • Avoid live vaccines during pregnancy, except when expected benefits to mother and baby outweigh risk © 2010 Canadian Paediatric Society I www.cps.ca

27. Precautions • Delay giving vaccine if child has: • Moderate to severe illness • People treated with blood products should not get a live vaccine (eg., measles, mumps, rubella, varicella) for 3 months or more. Depending on the blood product and dose received, these vaccines may not work • Don’t delay vaccination because of minor illness (eg., a cough or cold, with or without fever). © 2010 Canadian Paediatric Society I www.cps.ca

28. Diphtheria • Caused by a toxin made by bacteria that infect the nose, throat or skin • Can cause breathing problems, heart failure, nerve damage, kidney failure • About 1 person in 10 dies • Spread by close, direct contact withdroplets from a cough or sneeze • Before 1900, one of the main causes of childhood death. An estimated 12,000 cases/year in Canada, with 100 deaths • 1924: 9,000 cases in Canada • Routine immunization of Canadian children after 1930 • Since 1983:  5 cases/year, no deaths © 2010 Canadian Paediatric Society I www.cps.ca

29. Diphtheria vaccine • Inactivated bacterial toxin • Given with tetanus, acellular pertussis, polio and Hib vaccines as 5-in-1 • Also given with tetanus and pertussis as a booster in adolescence • Also given with tetanus as a booster—recommended every 10 years for adults • Common local reactions: redness, swelling, pain and tenderness at the injection site • Only contraindication: anaphylactic or other serious allergic reaction to a previous dose of the vaccine © 2010 Canadian Paediatric Society I www.cps.ca

30. Tetanus • Caused by a toxin made by bacteria that block normal control of nerve reflexes in the spinal cord: also known as “lockjaw” • Not contagious: Spread through spores (seed-like cells) in the environment, especially contaminated soil and dust • Before vaccine: 60-75 cases/year in Canada, with 40-50 deaths • Routine immunization began in 1944 • Today  2 cases/year in Canada • Since tetanus spores are in the environment, vaccination is the only means of prevention • Tetanus infection does not produce immunity to tetanus • In countries without vaccination, tetanus still kills © 2010 Canadian Paediatric Society I www.cps.ca

31. Tetanus vaccine • Inactivated bacterial toxin • Most often given with diphtheria, acellular pertussis, polio and Hib vaccines as 5-in-1 • Also given with diphtheria and pertussis as a booster in adolescence • Also given with diphtheria as a booster—recommended every 10 years for adults • Common local reactions: redness, swelling, pain and tenderness at the injection site • Only contraindication: an anaphylactic or other serious allergic reaction to a previous dose of the vaccine © 2010 Canadian Paediatric Society I www.cps.ca

32. Pertussis • Respiratory infection caused by bacteria: “whooping cough” • Causes severe coughing spells followed by a “whoop” sound • Lasts 6 to 12 weeks • 20-30% of infants with pertussis will be hospitalized • 1 in 400 infants will have brain damage • Very contagious: Spread by close, direct contact withdroplets from a cough or sneeze • Before vaccine: 30,000-50,000 cases/year with 50-100 deaths • Today: 3,000 cases in Canada, with about 5 deaths each year • Recent years: increasing number of cases in teens, young adults. Pertussis still a common cause of chronic cough (> 2 weeks) in teens and adults © 2010 Canadian Paediatric Society I www.cps.ca

33. Pertussis vaccine • Whole-cell vaccine introduced in Canada in 1943 • Acellularpertussis replaced whole-cell vaccine in 1997 • Purified bacterial proteins: fewer side effects • Given with diphtheria, tetanus, polio and Hib vaccines as 5-in-1 • Also given to older children, teens and adults as a booster, combined with Td • Immunizing parents, adults working with children protects babies too young to be fully immunized • Does not prevent infection in everyone but effective in reducing severity of illness and the risk of complications • Minor local side effects are common • Only contraindication: anaphylactic or other serious allergic reaction to a previous dose of the vaccine © 2010 Canadian Paediatric Society I www.cps.ca

34. Polio • Caused by poliovirus • Before 1955, a common infection in Canada • Most infections asymptomatic (no symptoms) or mild, but 1-5% cause meningitis and 1%, paralytic polio • Virus in throat and feces of people who are infected: spreads by close direct contact with throat secretions and indirect contact (eg., contaminated hands, water, food) • 1959: last epidemic in Canada, with 2,000 cases of paralytic polio • Children ages 5 to 9 years the most affected. • 1989: last case of paralytic polio due to poliovirus in Canada • 2008: still seen regularly in 4 countries, and can be spread by travellers © 2010 Canadian Paediatric Society I www.cps.ca

35. Polio vaccine • IPV (inactivated polio vaccine): killed, intact virus • Given with diphtheria, tetanus, pertussis and Hib vaccines as 5-in-1 • OPV (oral polio vaccine): live, attenuated virus. Not used in Canada since 1997-98, but still used in many countries • Side effects of IPV are rare • Effective and long-lasting: After 3 doses, 100% of infants develop antibodies against all 3 types of poliovirus • Only contraindication to IPV: an anaphylactic or other serious allergic reaction to a previous dose of the vaccine © 2010 Canadian Paediatric Society I www.cps.ca

36. Haemophilusinfluenzae type B (Hib) • Not to be confused with seasonal influenza or “flu” • Young children most at risk • Until 1985, the most common cause of bacterial meningitis in Canada: 1,500 cases/year in children  5 years old • Another 1,500 cases/year with serious infections (eg., of the blood, epiglottis, lungs, joints, bones and skin) • Meningitis: infection of the fluid and membranes covering the brain and spinal cord • Without treatment, all children with Hib meningitis die • Complications from Hib meningitis: brain damage, developmental delay, speech and language disorders, deafness • Not highly contagious: Hib bacteria in mouth, nose secretions spread by close, prolonged exposure or contact with droplets from a cough or sneeze A recent success story 1986: vaccine approved for use in Canada Since 2000: 5-16 cases/ yearof invasive Hib disease in children Hib disease is disappearing from every country with routine immunization for infants © 2010 Canadian Paediatric Society I www.cps.ca

37. Hib vaccine • Purified bacterial polysaccharide linked to a protein carrier, such as diphtheria or tetanus toxoid • Given with diphtheria, tetanus, pertussis and polio vaccines as 5-in-1 • Protects child against Hib and helps decrease spread among children generally • Local redness and pain in 5-15% of infants • Only contraindication: anaphylactic or other serious allergic reaction to a previous dose of the vaccine © 2010 Canadian Paediatric Society I www.cps.ca

38. Pneumococcal disease • Streptococcus pneumoniae: most common cause of meningitis and other invasive, serious bacterial infections in children in Canada, especially in children < 2 years of age • Older children, teens and adults with certain chronic conditions are also at higher risk • Infection starts in nose or throat. Many people are asymptomatic carriers (have no symptoms) • Not highly contagious, but spreads through close, direct contact: children in day care more at risk • Local infections: acute otitis media, acute sinusitis, acute bronchitis, pneumonia • Invasive infections: meningitis, bacteremia, septicemia, endocarditis, septic arthritis, osteomyelitis, peritonitis • Many pneumococci are becoming antibiotic-resistant A recent success story Since routine vaccination of infants began in 2005: 94% decrease in invasive disease in children < 2 years old Indirect effect: decreased exposure has led to a 91% decrease in invasive disease in the elderly © 2010 Canadian Paediatric Society I www.cps.ca

39. Pneumococcal vaccine • Two types available: polysaccharide and conjugate • Polysaccharide: not effective in children < 2 years of age. Used in older children, teens and adults. Contains the 23 serotypes that cause > 90% of serious infections • Conjugate: approved in 2001. Effective at 2 months of age. Contains • 7 serotypes. Vaccines containing 10 and 13 serotypes were recently licensed in Canada and have replaced the 7-serotype vaccine in some jurisdictions • Vaccines have dramatically reduced local and invasive forms of infections in all age groups • Strains that cause serious infections reduced by 40-50% • Local reactions: redness, swelling, pain and tenderness at injection site in • 10-20% of people • Only contraindication: an anaphylactic or other serious allergic reaction to a previous dose of the vaccine © 2010 Canadian Paediatric Society I www.cps.ca

40. Meningococcal disease • Neisseria meningitides:cancause meningitis, bacteremia, septicemia and other invasive infections • Before vaccine, 200-400 cases of invasive infection/year in Canada, with 20-40 deaths. Since 2001, rate in Canada has decreased, to about 200 cases/year • People with certain chronic diseases are at higher risk • Death from serious disease in 5% of cases, even with treatment, and can occur within 6-12 hours of first signs of illness • Meningococcal bacteria are fragile and infections are not very contagious • Most spread occurs via healthy carriers—about 1 in 5 adolescents and adults—by close, direct contact with mouth secretions, respiratory droplets • 5 serogroups (A, B, C, Y, and W135) cause nearly all infections in Canada, with Groups B and C causing the most illness • Infections caused by serogroups A, B, Y, and W135 will likely drop, now that conjugate quadrivalent vaccine (MCV4) is available in Canada © 2010 Canadian Paediatric Society I www.cps.ca

41. Meningococcal vaccine • A routine booster dose of either conjugate C or MCV4 is recommended for all children at about age 12 • More frequent boosters may be needed for people at higher risk of meningococcal infections • There is no vaccine available against type B meningococcus • Mild local reactions (redness, swelling, pain or tenderness at the infection site) reported for all vaccine types in 10-20% of people • Only contraindication is an anaphylactic or other serious allergic reaction to a previous dose of the vaccine © 2010 Canadian Paediatric Society I www.cps.ca

42. Measles • Severe viral infection. Causes high fever, runny nose, cough, conjunctivitis, rash of 1-2 weeks. Pneumonia is common (1-6% of cases) • Encephalitis: 1 in 1,000 cases, can lead to brain damage or death • Rare cases: SSPE (subacutesclerosingpanencephalitis) • Highly contagious: Spreads by direct contact and through the air. Germs become airborne in a cough or sneeze • Before vaccine: large epidemics every 2-3 years. Most children had measles, usually by 18 years of age • 300,000 cases/year in Canada, with 300 deaths and 300 children with brain damage • Vaccine approved in 1963; two-dose schedule in 1996-97 • 2001-06: fewer than 20 cases/year • 2007 outbreak in Quebec: 95 cases, almost all in persons who refused vaccination • 2008 outbreak in Ontario: in over 50 cases, most had received only one dose of vaccine or had never been vaccinated © 2010 Canadian Paediatric Society I www.cps.ca

43. Measles vaccine • Live, attenuated (weakened) virus • Given with mumps and rubella vaccines as MMR or with varicella as MMR-V • 2 doses required, since about 5% of vaccinated children remain unprotected after first dose • Mild side effects: fever (in 5-10% of children) or rash (in 2% of children) • Severe adverse events rare: risk of encephalitis is less than 1 case per one million doses • Noevidence of links to other diseases/disorders (such as autism, developmental delay, Crohn’s disease, ulcerative colitis) • Contraindications: • Allergic reaction to neomycin, gelatin, or a previous dose of the vaccine • Certain immune system disorders • Pregnancy • Precautions: • Delay vaccine for moderate to severe illness • Delay vaccine for 3 months or more for anyone who has received blood products, as the vaccine may not work © 2010 Canadian Paediatric Society I www.cps.ca

44. Mumps • Viral infection that can cause fever, headache and swelling of salivary glands around the jaw and cheeks • Can also cause a mild form of meningitis (in 1 in 10 cases) or severe encephalitis, leading to brain damage • Complications: deafness, swelling of testicles, infection of ovaries and (rarely) sterility • Virus in mouth and nose secretions spreads easily by close, direct contact and in droplets from a cough or sneeze • Before vaccine, over 30,000 cases/year reported in Canada • Vaccination programs began in the 1970s • Cases dropped to < 400/year with one-dose schedule, and to an average • 79 cases/year in 2000-06, with a two-dose schedule • Increasing numbers of cases in adolescents and young adults since 2007 may reflect waning immunity after single dose of vaccine © 2010 Canadian Paediatric Society I www.cps.ca

45. Mumps vaccine • Live, attenuated virus • Given in combination with measles and rubella vaccines as MMR or with varicella as MMR-V: 2 doses • Side effects are rare: Meningitis reported to occur in 1 case per 800,000 doses • Contraindications: • Allergic reaction to neomycin, gelatin, or a previous dose of the vaccine • Certain immune system disorders • Pregnancy • Precautions: • Delay vaccine for moderate to severe illness • Delay vaccine for 3 months or more for anyone who has received blood products, as the vaccine may not work © 2010 Canadian Paediatric Society I www.cps.ca

46. Rubella • Viral infection, also known as German measles • Can lead to fever, sore throat, swollen glands, rash • Usually mild in children. More severe in teens and adults: arthralgias, arthritis are common in adults • In pregnancy, can infect the fetus, causing severe disabilities: congenital rubella syndrome (CRS), which can result in heart disease, deafness, cataracts, mental retardation • Spreads by direct contact with mouth or nose secretions and droplets from a cough or sneeze. Less contagious than chickenpox or measles • Before vaccine, 85% of children had rubella by age 20: 250,000 cases/year, with 200 cases of congenital rubella syndrome • Worldwide epidemic in 1964: In U.S., ~30,000 babies infected during first • 20 weeks of pregnancy. Of those, ~20,000 cases of CRS and 8,000 deaths • Since routine immunization began in 1980: Only 0-3 babies with CRS are born in Canada each year to unvaccinated mothers © 2010 Canadian Paediatric Society I www.cps.ca

47. Rubella vaccine • Live, attenuated virus • Given to infants with measles and mumps vaccines as MMR or with varicella as MMR-V: 2 doses • Contraindications: • Allergic reaction to neomycin, gelatin, or a previous dose of vaccine • Certain immune system disorders • Pregnancy • Precautions: • Delay vaccine for moderate to severe illness • Delay vaccine for 3 months or more for anyone who has received blood products, as the vaccine may not work © 2010 Canadian Paediatric Society I www.cps.ca

48. Rubella vaccine and pregnancy • Women of child-bearing age should be tested for immunity to rubella before first pregnancy • Women not immune and not pregnant should be vaccinated • If pregnant and not immune, delay vaccine, but mother should be vaccinated as soon as possible after delivery for future protection • Side effects of vaccine rare in infants • 25% of vaccinated women experience joint pain © 2010 Canadian Paediatric Society I www.cps.ca

49. Varicella (chickenpox) • Caused by varicella-zoster virus • Fever, headache, aches and pains, and itchy rash • Usually a mild (but costly) disease: Parents often stay home for 3 days; 30-65% of children are brought to a clinic or hospital • Can lead to complications such as pneumonia, bacteremia, or severe skin infections • Illness is more severe, and complications more common, in teenagers and adults • Severe cases can pose serious health risks, especially for newborn babies, adults, or anyone with a weakened immune system • Highly contagious: Viruses from the throat and scratched skin lesions spread easily through the air. Also spreads by contact with rash • Contagious 2 days before rash appears until the last blister has crusted—usually about 5 days after rash begins • Virus remains dormant in the nervous system and can be reactivated later to cause shingles (zoster) A recent success story Before vaccine > 300,000 cases/year (95% of Canadians got chickenpox) Number of children hospitalized with varicella has dropped dramatically since vaccination programs began. By 2007, an 84% reduction in hospitalizations in provinces/territories with early (2000-02) programs; a 65% reduction for later (2004-06) programs © 2010 Canadian Paediatric Society I www.cps.ca

50. Varicella vaccine • Live, attenuated virus • 85-90% effective in preventing chickenpox and 100% effective in preventing moderate to severe disease • 2 doses of vaccine now recommended for all children > one year of age (previously, 2 doses given only to people vaccinated at ≥ 13 years of age) • Duration of protection at least 20 years—possibly lifelong • Mild local reactions in about 20% of children • Vaccine-modified disease does occur but is uncommon, and the illness less severe • Transmission of vaccine virus from healthy vaccinated children to susceptible contacts is rare • Given as varicella vaccine or in combination as MMR-V • Contraindications: • Allergic reaction to neomycin or gelatin, or to a previous dose of the vaccine • Certain immune system disorders • Pregnancy • Precautions: • Delay vaccine for moderate to severe illness • Delay vaccine for 3 months or more for anyone who has received blood products, as the vaccine may not work © 2010 Canadian Paediatric Society I www.cps.ca