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Control of Serogroup C Meningococcal Disease The Quebec Experience

Control of Serogroup C Meningococcal Disease The Quebec Experience. Philippe De Wals Université Laval Institut national de Santé publique. MENINGOCOCCAL DISEASE IN CANADA. C-MD Outbreaks: 1991 – 1994. YK. NUN. NWT. BC. AB. MB. SK. QC. NF. ON. PEI. NS. NB.

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Control of Serogroup C Meningococcal Disease The Quebec Experience

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  1. Control of Serogroup C Meningococcal Disease • The Quebec Experience Philippe De Wals Université Laval Institut national de Santé publique

  2. MENINGOCOCCAL DISEASE IN CANADA

  3. C-MD Outbreaks: 1991 – 1994 YK NUN NWT BC AB MB SK QC NF ON PEI NS NB

  4. Epidemiologic Situation in Quebec • Fall 1991 • Increased incidence of C-MD since 1990 • Spaciotemporal clustering • High incidence in adolescents • High fatality rate • Virulent C ET 15 clone

  5. Meningococcal Disease Cases 1990-1994 (Erickson et coll. 1998)

  6. Thymo-Independant Immune Response to Polysachharide Vaccine Antibodies Polysaccharide Lympho. B Plasma Cell.

  7. Bactericidal Antibodies One Month after MenC-PS-Vac Log GMT Age (King et al. J Pediatr 1996; 128: 196-202)

  8. Persistence of Anti-C Antibodies in Children Vaccinated Between 6 to 8 Years of Age (Lepow et al. Pediatrics 1977, 60: 673-680)

  9. Serogroup C PS Vaccine Trials in Military Recruits

  10. Cluster Immunization 1992-1993 • Region Date Nb vaccines Outaouais-Laurentide Jan 92 175 000 Sud Lanaudière Jan 92 48 000 Roberval Fév 92 3 000 Valleyfield Avr 92 11 000 Lakeshore Avr 92 4 000 Fermont Avr 92 1 000 Châteauguay Mai 92 10 000 Nord Lanaudière Oct 92 33 000

  11. Epidemiologic Situation Fall 1992 • Decreased incidence in vaccinated groups • New outbreaks and sporadic cases in unvaccinated groups

  12. MASS VACCINATION December 92- March 93 • Target : Population aged 6 mo to 20 yr • Vacciness : Bivalent PS & Tetravalent PS • Doses administered : 1 625 000 • Coeverage : 84% • Average vaccine purchase price = 5.26 $

  13. Vaccination Coverage Average = 84% % 6 mois 20 ans (De Wals et coll. Bull WHO 1996, 74: 2840-4)

  14. Costs of Campaign (x 1000 $) (Direction de la santé publique, 1994; Buteau et coll. 1998)

  15. Efficacy of Men-C-Vac According to Age

  16. Cumulative Incidence C-MD 1993-1998 (De Wals et coll. JAMA 2001, 285:177-81)

  17. Effectiveness of Mass Campaign (De Wals et coll. Vaccine 2002, 20:2840-4)

  18. Cost-Effectiveness of Mass Campaign (De Wals et coll. Vaccine 2002, 20:2840-4)

  19. Conjugate Meningococal Vaccines MCC-CRM197 (Chiron Vaccines – Menjugate) • 10 g serogroup C oligosaccharide conjugated with CRM197 protein (AlOH3) MCC-TT (Baxter {NAVA} – Neis Vac) • 10 g serogroup C polysaccharide (de-O-acetylated) conjugated with tetanus toxoid ( AlOH3) • MCC-CRM197 (Wyeth Lederle Vaccines - Meningitec) • 10 g serogroup C oligosaccharide conjugated with CRM197 protein (AlPO4)

  20. Proteine Antibodies Polysaccharide B Lympho. Plasma Cell. Thymo-Dépendent Immune Response to Conjugate Vaccine T Lympho. Memory Cell.

  21. SBA responses to MCC vaccines & 10 ug plain polysaccharide booster 6 months later in UK toddlers 10000 1000 SBA 100 GMT 10 1 50ug * Polysacc. naïve toddlers Pre- MCC Post MCC Pre- boost Post- boost

  22. MCC Vaccine Efficacy Estimates in the UK Subjects No. of Doses VE (95% CI) Infants Exactly 3 91.5% (64.9 - 98.0) Infants 2 or 3 88.6% (58.4 - 96.9) Infants Any 79.7% (38.2 - 93.3) Toddlers 1 89.3% (72.7 - 95.8) Pre-School* 1 100% (84.9 - 100) Years 1-11** 1 95.3% (88.3 - 98.6) Years 12/13*** 1 91.9% (73.3-98.4) * Pre-school = 3/4 yrs ** Year 1 to 11 = 4/5 yrs to 14/15 yrs *** Year 12/13 = 15 to 17 yrs

  23. Epidemiologic Situation • Spring 2001 • Increased incidence February 2001 • Spatiotemporal clustering • Adolescents • High fatality and sequelae rate • Virulent C 2a p1.1,7 ET15 Clone

  24. Number of Articles in Newspapers • January - September 2001 • La Presse 68 • Le Devoir 26 • Le Soleil 91

  25. Predicted Costs and Effectiveness of Mass Campaign

  26. MASS CAMPAIGN SPRING-FALL 2001 • No vaccinated : 48 000 MenC-PS & 1 804 000 MenC-Con • Coverage : 84% • Few adverse reactions • Decreased incidence • Two documented vaccine failures

  27. Usefulness of Mass Immunization Campaign

  28. Economic Evaluation of Routine Children Immunization • 25 birth cohorts • 75 000 births/yr • Follow-up  Age 25 yr • Study period 2002-2050 • $ 50 per dose • Discounting = 3%/yr

  29. Epidemiologic Scenarios Relative Probabilities 1) Endemicity 0.03 2) 1 epidemic 0.15 3) 2 epidemics 0.23 4) 3 epidemics 0.28 5) 4 epidemics 0.18 6) 5 epidemics 0.08 7) Hyperendemicity 0.02

  30. Immunization Strategies • Do nothing  • Routine 3 doses ( 2, 4 et à 6 mo) • Routine 1 dose (1 yr) • Mass campaign

  31. Health System Program Costs

  32. C-MD Incidence (1 outbreak) 100 90 80 cas 70 60 aucune vaccination 50 40 vaccination de masse 30 routine 1 dose 20 routine 3 doses 10 0 2002 2005 2008 2011 2014 2017 2020 2023 2026 2029 2032 2035 2038 2041 2044 2047 années 2050

  33. Societal Cost per C-MD Case Averted (x 1 0000 $)

  34. Incremental Cost-Effectiveness Ratio

  35. Average* Cost-Effectiveness RatioOne-Dose Strategy Cost per LY gained = 23 000 $ Cost per QALY gained = 39 000 $ *Weighted-average of probabilities of 7 scenarios

  36. Meningococcal Programs in Canada • Alberta : 3 doses (after mass campaign) • Quebec : 1 dose (after masss campaign) • British Columbia : 1 dose (& catch-up)

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