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Manuel_and_Kwong_CDC..

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  • 1. Enhancing the effectiveness of health care for Ontarians through research Ontario’s Experience with a Universal Influenza Immunization Program (UIIP) Doug Manuel, MD MSc FRCPC Scientist Jeff Kwong, MD MSc CCFP Research Fellow October 25, 2005
  • 2. Enhancing the effectiveness of health care for Ontarians through research Outline • Background • Effect of UIIP on vaccination rates • Effect of UIIP on hospitalizations • Discussion & conclusions
  • 3. Enhancing the effectiveness of health care for Ontarians through research A brief geography lesson…
  • 4. Enhancing the effectiveness of health care for Ontarians through research 12M 7M 4M 3M 1M 1M 0.5M 1M 0.1M 0.7M 30K 30K 40K Population by province/territory as of July 1, 2004
  • 5. Enhancing the effectiveness of health care for Ontarians through research Influenza vaccination in Canada • All health care services are publicly funded and delivered, but programs vary by province • Ontario, pre-2000  1988: Targeted program initiated to provide influenza vaccination free for those at high risk of complications from influenza (elderly 65+, those with chronic medical conditions)  1993: Program expanded to cover patient-care staff of long term care facilities (LTCF)  1999: Program expanded to cover ALL health care workers
  • 6. Enhancing the effectiveness of health care for Ontarians through research Ontario launches UIIP in 2000 • First large-scale program to provide free influenza vaccination to entire population aged 6 months or older • Stated goals: to decrease influenza- related morbidity and mortality, and to decrease ER overcrowding • All other provinces chose to maintain their targeted vaccination programs
  • 7. Enhancing the effectiveness of health care for Ontarians through research Some details about the UIIP • Vaccines (trivalent inactivated vaccine) purchased centrally by Ministry of Health and Long-Term Care from 2 manufacturers: Sanofi-Pasteur and Shire Biologics • Vaccines delivered at MD offices, LTC facilities, hospitals, public health units, workplace clinics, pharmacies, schools, community centers, shopping malls, etc.
  • 8. Enhancing the effectiveness of health care for Ontarians through research Locations where people were vaccinated in Ontario, 2000-01 0 10 20 30 40 50 60 70 Clinic/walk-in clinic Hospital Other School Public health unit Community health centre Work Doctor's office Percentage of respondents (%)
  • 9. Enhancing the effectiveness of health care for Ontarians through research More details about the UIIP • Extensive communications campaign by provincial government and local public health units to promote UIIP, including TV/radio/print advertising, newsletters, mailings, billboards, web sites, etc. • Response has been generally favorable by the public and those involved in delivery of vaccines
  • 10. Enhancing the effectiveness of health care for Ontarians through research Estimated costs of the UIIP • Total program cost: ~$42M CDN* (2003-04)  Vaccine purchase (~54%)  Vaccine delivery & administration (~34%)  Communications (~12%) * $1CDN = $0.85US as of Oct 17, 2005
  • 11. Enhancing the effectiveness of health care for Ontarians through research Effect of Ontario’s UIIP on vaccination rates
  • 12. Enhancing the effectiveness of health care for Ontarians through research Research Questions • Did introduction of Ontario’s UIIP in 2000 lead to an increase in vaccination rates, compared to the 9 provinces that maintained targeted immunization programs? • If so, which population subgroups benefited the most?
  • 13. Enhancing the effectiveness of health care for Ontarians through research Data sources • National Population Health Survey (NPHS) • Canadian Community Health Survey (CCHS) • Both conducted by Statistics Canada  Cover the household population  Exclude members of the Canadian Forces, native reserves, and some remote areas, those living in institutions (e.g., nursing homes, prisons)
  • 14. Enhancing the effectiveness of health care for Ontarians through research Population health surveys NPHS 1996/97 CCHS 1.1 2000/01 CCHS 2.1 2003 Data collection Jun 1996 to Aug 1997 Jun to Aug 2001 (Q4) Jan to Dec 2003 Response rate 83% 85% 81% Sample 73,402 35,187 133,026 Weighted population 24.6 million 25.9 million 26.5 million
  • 15. Enhancing the effectiveness of health care for Ontarians through research Unpublished results to be presented
  • 16. Enhancing the effectiveness of health care for Ontarians through research Summary of findings • Influenza vaccination rates increased across Canada between 1996 & 2003 • Introduction of UIIP in Ontario associated with a significant increase in coverage rate of overall population aged 12+ years compared to other provinces, with the increase accounted for by those aged 12-64 years
  • 17. Enhancing the effectiveness of health care for Ontarians through research Median coverage rates in LTC facility residents & staff, hospital staff • Since 1999, coverage rates as of Nov 15 provided annually by facilities to public health officials 1999-00 2000-01 2001-02 2002-03 2003-04 Residents 93% 95% 96% 95% 95% LTC Staff 86% 90% 86% 82% 84% Hosp Staff N/A 63%* 51% 44% 55% * Includes those vaccinated in Dec and Jan
  • 18. Enhancing the effectiveness of health care for Ontarians through research Effect of Ontario’s UIIP on hospitalizations
  • 19. Enhancing the effectiveness of health care for Ontarians through research Research Questions • Did introduction of Ontario’s UIIP in 2000 lead to a reduction in influenza- related hospitalizations, compared to the 9 provinces that maintained targeted immunization programs? • If so, which population subgroups benefited the most?
  • 20. Enhancing the effectiveness of health care for Ontarians through research Methods • Study design: Interrupted time series with concurrent controls • Study population and setting: All residents of 10 Canadian provinces, September 1993 to March 2004
  • 21. Enhancing the effectiveness of health care for Ontarians through research Hospitalization data • Obtained from Hospital Morbidity Database • Included admissions with the following conditions listed as 1 of the first 5 diagnoses Diagnoses (Dx) ICD-9 Codes ICD-10 Codes Pneumonia & Influenza (P&I) 480-487 J10-18 Acute Respiratory Diseases (ARD) 460-466 J00-06, J20-22 Chronic Obstructive Pulmonary Disease (COPD) 490-492, 496 J40-44
  • 22. Enhancing the effectiveness of health care for Ontarians through research Definition of influenza season • From October to May, starting when each week accounted for ≥ 5% of the season’s total number of influenza virus isolates for 2 weeks and ending when the influenza isolates accounted for < 5% for 2 weeks *Adapted from Izurieta HS, et al. NEJM 2000; 342(4):232-9
  • 23. Enhancing the effectiveness of health care for Ontarians through research Viral surveillance data • Respiratory virus detections  Weekly percentage of tests positive for influenza A, influenza B, RSV • Predominant influenza subtypes  Subtype considered predominant if detections accounted for ≥ 20% of the season’s isolates • Vaccine antigenic match  Compared mismatch between circulating strains and vaccine strains • Good match: < 20% circulating strains mismatched • Fair match: 20-50% circulating strains mismatched • Poor match: > 50% circulating strains mismatched
  • 24. Enhancing the effectiveness of health care for Ontarians through research Statistical analysis • Poisson regression models*  Run separately for each condition and province, for 7 age groups: 0-4, 5-19, 20- 49, 50-64, 65-74, 75-84, 85+  Accounted for numerous covariates  Used generalized estimating equations to control for autocorrelation – AR(1) *Adapted from Thompson, et al. JAMA 2004; 292(11):1333-40
  • 25. Enhancing the effectiveness of health care for Ontarians through research Poisson regression model Y = α exp (β0 + β1[UIIP_flu] + β2[sex*agegrp] + β3[%FluA] + β4[%FluB] + β5[%RSV] + β6[A(H1N1)] + β7[A(H3N2)] + β8[B] + β9[match] + β10[ICD-10] + β11[t] + β12[t2 ] + β13[t3 ] + β14-16[sin(2tkπ/52)] + β17-19[cos(2tkπ/52)] [where k=1, 2, 3] + ε)
  • 26. Enhancing the effectiveness of health care for Ontarians through research Poisson model terms Y = weekly number of condition-specific hospitalizations for a given province-, sex-, and age group-stratum α = log of province-, sex- and age group-specific annual population size UIIP_flu = RR of hospitalizations during influenza seasons after 2000 vs. before sex*agegrp = sex & age group interaction %FluA/FluB/RSV = weekly % of regional tests positive for influenza A/B, RSV A(H1N1)/A(H3N2)/B = predominant influenza subtype(s) for a season [1/0] match = vaccine antigenic match [G/F/P] ICD-10 = introduction of ICD-10 t, t2 , t3 = time trend terms [t=week number divided by 52] sin/cos = seasonal trend terms
  • 27. Enhancing the effectiveness of health care for Ontarians through research Statistical analysis cont’d • Compared RR estimates of change in influenza season-associated hospitalizations over time for Ontario with pooled estimates for other provinces combined • Pooled RR estimates for separate age groups to estimate effect on overall pop. • Pooled RR estimates for separate conditions to estimate combined effect on the 3 influenza-related conditions
  • 28. Enhancing the effectiveness of health care for Ontarians through research Unpublished results to be presented
  • 29. Enhancing the effectiveness of health care for Ontarians through research Discussion & Conclusions
  • 30. Enhancing the effectiveness of health care for Ontarians through research Limitations • Data quality concerns with health administrative data (coding validity/reliability) • No vaccine coverage data on children < 12 years or institutionalized elderly (outside ON) • Provincial-level analysis – may have blurred regional variations in timing and severity of influenza epidemics and hospitalization rates • Ecological study design – susceptible to ecological fallacy • Unmeasured confounders
  • 31. Enhancing the effectiveness of health care for Ontarians through research Lessons learned • Implementation of a universal influenza vaccination program is feasible • Clear increases in vaccination rates observed in younger age groups, and increases generally sustained • Modest reductions in influenza-related hospitalizations observed in groups with larger increases in coverage rates  Suggests direct benefit of influenza vaccination  Uncertain about indirect benefits (herd immunity)
  • 32. Enhancing the effectiveness of health care for Ontarians through research Critical information gaps • Suboptimal data on individual-level vaccination status (no immunization registry) • Effect of UIIP on other outcomes (outpatient MD visits, ER services, mortality) to be examined by early 2006 • Effect of UIIP on school and workplace absenteeism should also be assessed • No data on vaccination rates in those < 12 yrs • Economic evaluation based on empirical outcome data needed
  • 33. Enhancing the effectiveness of health care for Ontarians through research Future studies • Examine other outcomes • Repeat time series analyses with additional data (i.e., more influenza seasons) • Cross-sectional study to examine the relationship between regional variations in vaccination rates and outcome rates in post-UIIP Ontario (to look for a dose- response relationship)
  • 34. Enhancing the effectiveness of health care for Ontarians through research Acknowledgements • ICES  Therese Stukel, Jenny Lim, Laura Fazio • Statistics Canada  Helen Johansen, Christie Sambell • Public Health Agency of Canada  Peter Zabchuk • CDC  Bill Thompson, David Shay • Others  Ross Upshur, Allison McGeer, Susan Tamblyn, Irfan Dhalla
  • 35. Enhancing the effectiveness of health care for Ontarians through research Financial support • This research was supported by a grant from the Public Health Agency of Canada • Doug Manuel is supported by a Career Scientist award from Ontario’s Ministry of Health and Long-Term Care • Jeff Kwong is supported by a CIHR Fellowship award from the Canadian Institutes of Health Research
  • 36. Enhancing the effectiveness of health care for Ontarians through research Questions?