Post on 28-Dec-2015
Epidemiology of Epidemiology of Hepatitis C Infection Hepatitis C Infection in Canadain CanadaRobert S. Remis MD, MPH, Robert S. Remis MD, MPH, FRCPCFRCPC
Department of Public Health SciencesDepartment of Public Health SciencesUniversity of TorontoUniversity of Toronto
1st Canadian Conference on Hepatitis 1st Canadian Conference on Hepatitis CCMontreal, QuebecMontreal, Quebec
May 1-4, 2001May 1-4, 2001
instructional media centre, Laboratories Branch – 2001
AcknowledgementsAcknowledgements
Hepatitis C Transfusion Working Group, June 1998Hepatitis C Transfusion Working Group, June 1998 Robert S. Hogg, Murray D. Krahn, Robert W.H. Palmer, Jutta Robert S. Hogg, Murray D. Krahn, Robert W.H. Palmer, Jutta
K. Preiksaitis, Morris Sherman K. Preiksaitis, Morris Sherman
in collaboration within collaboration with JoAnne Chiavetta, PhD, Martin Tepper MD, JoAnne Chiavetta, PhD, Martin Tepper MD,
Shimian Zou MD and Bob Slinger MDShimian Zou MD and Bob Slinger MD
HCV-HIV Study, February 2000-March 2001HCV-HIV Study, February 2000-March 2001 Marcel DuBois, Chris Archibald, Jennifer GeduldMarcel DuBois, Chris Archibald, Jennifer Geduld Morris Sherman, Kevin Craib, Shimian ZouMorris Sherman, Kevin Craib, Shimian Zou
OthersOthers Michel Alary, Kevin Craib, Elaine WhittinghamMichel Alary, Kevin Craib, Elaine Whittingham
instructional media centre, Laboratories Branch – 2001
BackgroundBackground
Importance of hepatitis C was underestimated Importance of hepatitis C was underestimated due to delay in recognizing infectiondue to delay in recognizing infection
difficulties in developing diagnostic toolsdifficulties in developing diagnostic toolslong latency from infection to diseaselong latency from infection to disease
Need to better evaluate extent and Need to better evaluate extent and distribution distribution of HCV infection in Canadaof HCV infection in Canadadevelop appropriate guidelines for primary preventiondevelop appropriate guidelines for primary preventiondevelop guidelines for HCV testingdevelop guidelines for HCV testingassess burden of infection and disease in shortassess burden of infection and disease in short
and long term and long term plan appropriate health services and support programsplan appropriate health services and support programs
instructional media centre, Laboratories Branch – 2001
Overview of presentationOverview of presentation
1. Review of literature (published & 1. Review of literature (published & unpublished)unpublished)
2. Hepatitis C transmitted by blood 2. Hepatitis C transmitted by blood transfusiontransfusion
3. Hepatitis C prevalence and incidence in 3. Hepatitis C prevalence and incidence in CanadaCanada
4. Estimating number of persons in 4. Estimating number of persons in Canada with dual HCV-HIV infection Canada with dual HCV-HIV infection
5. Conclusions5. Conclusions
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Selected seroepidemiologic Selected seroepidemiologic studies among IDUsstudies among IDUs
Author
Population
Location
Study year
Sample size
HCV prevalence
Strathdee IDUs Vancouver 1996-97 1,006 88%
Lamothe IDUs Montreal 1992-96 282 70% Incidence 27%
LCDC IDUs CBI Nova Scotia
1996-97 92 47%
Romanowski IDUs STD clinic
Alberta 1994-95 6,668 41% Men 46%
Women 31%
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Selected seroepidemiologic Selected seroepidemiologic studies among prisonersstudies among prisoners
Author Population LocationStudyyear
Samplesize
HCVprevalence
Prefontaine Males BritishColumbia
1990 415 26%
Ford Females Kingston,Ontario
1994 133 40%
Ford Males Kingston,Ontario
1998 350 33%IDU 73%
Non-IDU 9.6%
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Selected seroepidemiologic Selected seroepidemiologic studies among patient studies among patient populationspopulations
Author Population Location Study year
Sample size
HCV prevalence
Romanowski Non-IDUs STD clinic
Alberta 1994-95 6,668 0.89% Men 1.2%
Women 0.54%
Ali Hemophilia patients
Newfoundland 1990? 66 33% 83% FCs <
1996
Manuel Patients in HBV outbreak
Metro Toronto
1996 6,055 0.7% (standardized)
Armstrong Cornea donors
Ontario 1993-96 3,228 0.93%
Scully Sexual partners of HCV+
Ottawa, Ontario
1992? 29 0.00%
instructional media centre, Laboratories Branch – 2001
Selected seroepidemiologic Selected seroepidemiologic studies among variousstudies among variouspatient populationspatient populations
Author Population LocationStudyyear
Samplesize
HCVprevalence
Louie Hospitalpatients
Toronto,Ontario
1990 3,000 0.54%
Joly Sentinelhospital daysurgery pts
Quebec 1990-92 10,164 0.58%Men 0.55%
Women 0.60%
Pi Pregnantwomen
BritishColumbia
1994 15,000 0.9%
Craib MSM Vancouver,BritishColumbia
1982-98 623 5.9%IDU 49%
Non-IDU 3.1%
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Hepatitis C infection due to Hepatitis C infection due to blood transfusion: Methodsblood transfusion: Methods
Model 1Model 1 For each year, number of transfused For each year, number of transfused units x HCV risk per unitunits x HCV risk per unit
Used survival function to calculate number Used survival function to calculate number of of
recipients surviving to July 1998recipients surviving to July 1998
Model 2Model 2 Estimated number of HCV-infected persons Estimated number of HCV-infected persons in Canada as of July 1998in Canada as of July 1998
Calculated proportion and number due to Calculated proportion and number due to blood transfusionblood transfusion
Model 3Model 3 Estimated number of persons transfused Estimated number of persons transfused in Canadain Canada
Calculated proportion and number with Calculated proportion and number with HCV infectionHCV infection
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Modeled HCV risk and number of Modeled HCV risk and number of HCV-infected transfusion HCV-infected transfusion recipients, 1980–1991recipients, 1980–1991
Year of transfusion
HCV risk per unit
HCV risk per episode
Number of HCV
infections
Number surviving to
1998
1980 0.400% 2.1% 4,790 1,560
1981 0.400% 2.1% 5,090 1,720
1982 0.400% 2.1% 5,380 1,880
1983 0.383% 2.1% 5,580 2,020
1984 0.356% 1.9% 5,630 2,110
1985 0.317% 1.7% 5,190 2,010
1986 0.278% 1.5% 4,500 1,800
1987 0.246% 1.3% 3,880 1,600
1988 0.223% 1.2% 3,430 1,460
1989 0.201% 1.1% 3,050 1,340
1990a 0.185% 0.99% 850 390
1990b 0.035% 0.19% 520 250
1991 0.017% 0.09% 320 160
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Modeled HCV risk per transfusion Modeled HCV risk per transfusion episode and number of HCV-episode and number of HCV-infected transfusion recipients, infected transfusion recipients, 1980-19911980-1991
0.00%
0.10%
0.20%
0.30%
0.40%
0.50%
1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990a 1990b 1991
Year of transfusion
Per
un
it H
CV
ris
k
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Modeled number of surviving Modeled number of surviving HCV-infected transfusion HCV-infected transfusion recipients recipients by period of transfusion,1980–by period of transfusion,1980–19921992
Period oftransfusion
Number oftransfusion-associated
HCV infectionsProportion
of total Plausible limits1960-85 27,700 80% (19,800 - 38,200)
1986-90 6,600 19% (5,200 - 8,100)
1990-92 450 1% (390 - 520)
Total 34,800 100% (26,600 - 45,400)
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Modeled number of surviving Modeled number of surviving HCV-infected transfusion HCV-infected transfusion recipients recipients by period of transfusion by period of transfusion (n=34,800)(n=34,800)
1990-921%
1986-8919%
1960-8580%
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Modeled number of surviving Modeled number of surviving HCV-infected transfusion HCV-infected transfusion recipients recipients by period of transfusion 1980–by period of transfusion 1980–19921992
0 0.5 1 1.5 2
Rate (/1,000)
Ontario
British Columbia
Quebec
Alberta
Manitoba
Nova Scotia
Saskatchewan
New Brunswick
Newfoundland
PEI
Canada 34,790
50
70
420
630
700
900
3,700
5,290
7,660
15,370
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Hepatitis C prevalence and Hepatitis C prevalence and incidence, 1998: Methodsincidence, 1998: Methods
From HCV transfusion Model 2, From HCV transfusion Model 2, estimated prevalent HCV infectionsestimated prevalent HCV infections
Interpolated to each provincesInterpolated to each provinces
Using population-based data (limited)Using population-based data (limited)
Estimating relative population prevalence Estimating relative population prevalence from first-time blood donorsfrom first-time blood donors
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Modeled number of HCV-infected Modeled number of HCV-infected persons by province, 1998 persons by province, 1998 (n=(n=240,000)240,000)
0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40%
HCV Prevalence
Ontario
British Columbia
Quebec
Alberta
Manitoba
Nova Scotia
Saskatchewan
New Brunswick
Newfoundland
PEI 340
460
2,800
4,300
4,800
6,200
25,400
36,200
52,500
105,200
instructional media centre, Laboratories Branch – 2001
Modeled number of Modeled number of HCV-infected persons HCV-infected persons by province (n=by province (n=240,000)240,000)
22.0%
1.8%
1.2%
0.2%
0.1%
2.0%
2.6% 10.7%
15.2%
44.2%
OntarioBritish ColumbiaQuebecAlbertaManitobaNova ScotiaSaskatchewanNew BrunswickNewfoundlandPEI
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HypotheticalHypothetical number of number of HCV-infected persons in Canada HCV-infected persons in Canada by mode of transmissionby mode of transmission
Mode oftransmission Number at risk
HCVprevalence
HCVnumber
Proportion(%) Plausible limits
Transfusionrecipients
2,700,000 1.3% 35,000 15%
Active IDUs 90,000 75% 68,000 28%
Ex-IDUs 180,000 40% 72,000 30%
Total IDUs 270,000 52% 140,000 58%
Other 27,000,000 0.24% 65,000 27%
Total 30,000,000 0.80% 240,000 100% (215,000 - 275,000)
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Annual incidence of Annual incidence of HCV infection in Canada:HCV infection in Canada:Preliminary perspectivesPreliminary perspectives
Method 1Method 1 Observed incidence among Observed incidence among populations in populations in
sentinel surveillance study projected sentinel surveillance study projected from from
proportion symptomatic to all HCV proportion symptomatic to all HCV infectionsinfections
Method 2Method 2 Observed HCV incidence Observed HCV incidence among among susceptible susceptible IDUs in study IDUs in study cohorts cohorts projected from proportion projected from proportion IDU to all IDU to all HCV infections HCV infections
(90,000 IDU - 68,000 HCV) x 20%(90,000 IDU - 68,000 HCV) x 20%
Preliminary estimate: 3,000 - 8,000 new Preliminary estimate: 3,000 - 8,000 new HCV infections per year HCV infections per year
instructional media centre, Laboratories Branch – 2001
HCV infections in Canada:HCV infections in Canada:InterpretationInterpretation Estimates are subject to considerable Estimates are subject to considerable
uncertainty due to very limited Canadian uncertainty due to very limited Canadian data from representative study populations data from representative study populations (only one study, in Quebec)(only one study, in Quebec)
HCV prevalence appears highest in British HCV prevalence appears highest in British Columbia, Ontario and Alberta. Four Columbia, Ontario and Alberta. Four provinces, British Columbia, Ontario, provinces, British Columbia, Ontario, Quebec and Alberta account for ~92% of Quebec and Alberta account for ~92% of HCV infections in CanadaHCV infections in Canada
The majority (>50%) of prevalent HCV The majority (>50%) of prevalent HCV infections in Canada are among IDUs, where infections in Canada are among IDUs, where HCV prevalence is >100-fold greater than HCV prevalence is >100-fold greater than other Canadians taken as a wholeother Canadians taken as a whole
instructional media centre, Laboratories Branch – 2001
Estimating the number of persons Estimating the number of persons in in Canada with dual HCV-HIV Canada with dual HCV-HIV infection:infection:MethodsMethods
1. Estimate the number of HIV-infected 1. Estimate the number of HIV-infected persons by HIV-defined exposure category persons by HIV-defined exposure category and geographic regionand geographic region
2.2. Estimate HCV prevalence in each group Estimate HCV prevalence in each group (obtain data from available studies and (obtain data from available studies and review by expert consensus panel)review by expert consensus panel)
3.3. Multiply number by HCV prevalenceMultiply number by HCV prevalence
4.4. Plausible limits of outcome using Monte Plausible limits of outcome using Monte Carlo simulationCarlo simulation
5.5. Special analysis for Aboriginal population Special analysis for Aboriginal population and prisoners to estimate persons in each and prisoners to estimate persons in each HIV-defined exposure category and then as HIV-defined exposure category and then as aboveabove
instructional media centre, Laboratories Branch – 2001
Modeled number of HCV-HIV Modeled number of HCV-HIV infected persons by exposure infected persons by exposure category, 1999category, 1999
MSM MSM-IDU IDU EndemicOtherhetero
Clottingfactors Transfused
Total
Number 1,193 1,648 7,921 63 118 237 15 11,194
Proportion 11% 15% 71% 0.6% 1.1% 2.1% 0.1% 100%
Lower 95%limit
760 1,200 6,300 41 56 190 11 9,400
Upper 95%limit
1,800 2,200 9,900 88 220 300 21 13,300
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Modeled number of HCV-HIV Modeled number of HCV-HIV infected persons by exposure infected persons by exposure category, 1999 (n=11,194)category, 1999 (n=11,194)
15%
0.1%2.1%
1.1%0.6%
71%
11%
MSM
MSM-IDU
IDU
Endemic
Other hetero
Clottingfactors
Transfusion
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Modeled number of HCV-HIV Modeled number of HCV-HIV infected persons by geographic infected persons by geographic region, 1999 (n=11,194)region, 1999 (n=11,194)
34%
1.0%1.7%
3.3%
6.8%
29%
25%
Ontario
Quebec
British Columbia
Alberta
Prairies
Atlantic
Yukon / NWT
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Modeled number of HCV-HIV Modeled number of HCV-HIV infected Aboriginal people infected Aboriginal people by exposure category, 1999by exposure category, 1999 (n=(n=1,477)1,477)
10%
87%
1.8%
0.2%0.4%
0.9%
MSM
MSM-IDU
IDU
Other hetero
Clotting factors
Transfusion
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Modeled number of HCV-HIV Modeled number of HCV-HIV infected prisoners infected prisoners by exposure category, 1999 by exposure category, 1999 (n=611)(n=611)
11%
88%
0.6%0.0%
0.0%
0.9%0.0%
MSMMSM-IDUIDUEndemicOther heteroClottingfactorsTransfusion
instructional media centre, Laboratories Branch – 2001
ConclusionsConclusions
Current estimates of HCV infections must be Current estimates of HCV infections must be considered as hypotheses, not as conclusions; considered as hypotheses, not as conclusions; the epidemiology of HCV infection in Canada the epidemiology of HCV infection in Canada remains largely unknown. remains largely unknown.
Population-based studies are necessaryPopulation-based studies are necessary
Burden of HCV infection is greatest in four Burden of HCV infection is greatest in four provinces which account for most HCV infections provinces which account for most HCV infections in Canadain Canada
Most new HCV infections are probably among Most new HCV infections are probably among IDUs but a substantial proprtion, possibility as IDUs but a substantial proprtion, possibility as many as 40%, are not related to injectionmany as 40%, are not related to injection
Transmission of HCV (probability, determinants) Transmission of HCV (probability, determinants) in other populations needs further elucidationin other populations needs further elucidation