Epidemiology of
Hepatitis C Infection
in Canada
Robert S. Remis MD, MPH, FRCPC
Department of Public Health Sciences
University of Toronto
1st Canadian Conference on Hepatitis C
Montreal, Quebec
May 1-4, 2001
Acknowledgements
Hepatitis C Transfusion Working Group, June 1998
 Robert
S. Hogg, Murray D. Krahn, Robert W.H. Palmer, Jutta K.
Preiksaitis, Morris Sherman
in collaboration with
 JoAnne
Chiavetta, PhD, Martin Tepper MD,
Shimian Zou MD and Bob Slinger MD
HCV-HIV Study, February 2000-March 2001
 Marcel
DuBois, Chris Archibald, Jennifer Geduld
 Morris
Sherman, Kevin Craib, Shimian Zou
Others
 Michel Alary,
Kevin Craib, Elaine Whittingham
instructional media centre, Laboratories Branch – 2001
Background
Importance of hepatitis C was underestimated
due to delay in recognizing infection
 difficulties
 long
in developing diagnostic tools
latency from infection to disease
Need to better evaluate extent and distribution
of HCV infection in Canada
 develop
appropriate guidelines for primary prevention
 develop
guidelines for HCV testing
 assess
burden of infection and disease in short
and long term
 plan
appropriate health services and support programs
instructional media centre, Laboratories Branch – 2001
Overview of presentation
1. Review of literature (published & unpublished)
2. Hepatitis C transmitted by blood transfusion
3. Hepatitis C prevalence and incidence in Canada
4. Estimating number of persons in Canada with
dual HCV-HIV infection
5. Conclusions
instructional media centre, Laboratories Branch – 2001
Selected seroepidemiologic
studies 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
Alberta
1996-97
92
47%
1994-95
6,668
41%
Men 46%
Women 31%
Romanowski IDUs
STD clinic
instructional media centre, Laboratories Branch – 2001
Selected seroepidemiologic
studies among prisoners
Author
Population
Location
Study
year
Sample
size
HCV
prevalence
Prefontaine
Males
British
Columbia
1990
415
26%
Ford
Females
Kingston,
Ontario
1994
133
40%
Ford
Males
Kingston,
Ontario
1998
350
33%
IDU 73%
Non-IDU 9.6%
instructional media centre, Laboratories Branch – 2001
Selected seroepidemiologic
studies among patient populations
Study
year
1994-95
Sample
size
6,668
HCV
prevalence
0.89%
Men 1.2%
Women 0.54%
66
33%
83% FCs <
1996
0.7%
(standardized)
Author
Population
Romanowski Non-IDUs
STD clinic
Location
Alberta
Ali
Hemophilia
patients
Newfoundland
1990?
Manuel
Patients in
HBV
outbreak
Cornea
donors
Metro Toronto
1996
6,055
Ontario
1993-96
3,228
0.93%
Sexual
partners of
HCV+
Ottawa,
Ontario
1992?
29
0.00%
Armstrong
Scully
instructional media centre, Laboratories Branch – 2001
Selected seroepidemiologic
studies among various
patient populations
Author
Louie
Population
Hospital
patients
Location
Toronto,
Ontario
Joly
Sentinel
hospital day
surgery pts
Quebec
Pi
Pregnant
women
British
Columbia
Craib
MSM
Vancouver,
British
Columbia
instructional media centre, Laboratories Branch – 2001
Study
year
1990
Sample
size
3,000
HCV
prevalence
0.54%
1990-92
10,164
0.58%
Men 0.55%
Women 0.60%
1994
15,000
0.9%
623
5.9%
IDU 49%
Non-IDU 3.1%
1982-98
Hepatitis C infection due to
blood transfusion: Methods
Model 1
For each year, number of transfused
units x HCV risk per unit
Used survival function to calculate number of
recipients surviving to July 1998
Model 2
Estimated number of HCV-infected persons
in Canada as of July 1998
Calculated proportion and number due to
blood transfusion
Model 3
Estimated number of persons transfused
in Canada
Calculated proportion and number with
HCV infection
instructional media centre, Laboratories Branch – 2001
Modeled HCV risk and number of
HCV-infected transfusion recipients,
1980–1991
Year of
HCV risk per HCV risk per
transfusion
unit
episode
1980
0.400%
2.1%
1981
0.400%
2.1%
1982
0.400%
2.1%
1983
0.383%
2.1%
1984
0.356%
1.9%
1985
0.317%
1.7%
1986
0.278%
1.5%
1987
0.246%
1.3%
1988
0.223%
1.2%
1989
0.201%
1.1%
1990a
0.185%
0.99%
1990b
0.035%
0.19%
1991
0.017%
0.09%
instructional media centre, Laboratories Branch – 2001
Number of
HCV
infections
4,790
5,090
5,380
5,580
5,630
5,190
4,500
3,880
3,430
3,050
850
520
320
Number
surviving to
1998
1,560
1,720
1,880
2,020
2,110
2,010
1,800
1,600
1,460
1,340
390
250
160
Modeled HCV risk per transfusion
episode and number of HCV-infected
transfusion recipients, 1980-1991
Per unit HCV risk
0.50%
0.40%
0.30%
0.20%
0.10%
0.00%
1980
1981
1982
1983
1984
1985
1986
1987
1988
Year of transfusion
instructional media centre, Laboratories Branch – 2001
1989 1990a 1990b 1991
Modeled number of surviving
HCV-infected transfusion recipients
by period of transfusion,1980–1992
Period of
transfusion
Number of
transfusionassociated
HCV infections
Proportion
of total
Plausible limits
1960-85
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)
instructional media centre, Laboratories Branch – 2001
Modeled number of surviving
HCV-infected transfusion recipients
by period of transfusion (n=34,800)
1960-85
80%
1986-89
19%
1990-92
1%
instructional media centre, Laboratories Branch – 2001
Modeled number of surviving
HCV-infected transfusion recipients
by period of transfusion 1980–1992
Canada
34,790
PEI
50
N ewfoundland
70
N ew Brunswick
420
Saskatchewan
630
N ova Scotia
700
M anitoba
900
Alberta
3,700
Quebec
5,290
British Columbia
7,660
Ontario
15,370
0
0.5
1
Rate (/1,000)
instructional media centre, Laboratories Branch – 2001
1.5
2
Hepatitis C prevalence and
incidence, 1998: Methods
 From
HCV transfusion Model 2,
estimated prevalent HCV infections
 Interpolated
Using
to each provinces
population-based data (limited)
Estimating
relative population prevalence
from first-time blood donors
instructional media centre, Laboratories Branch – 2001
Modeled number of HCV-infected
persons by province, 1998
(n=240,000)
PEI
Newfoundland
340
460
New Brunswick
Saskatchewan
Nova Scotia
Manitoba
2,800
4,300
4,800
6,200
Alberta
Quebec
25,400
36,200
British Columbia
Ontario
52,500
105,200
0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 1.20% 1.40%
HCV Prevalence
instructional media centre, Laboratories Branch – 2001
Modeled number of
HCV-infected persons
by province (n=240,000)
22.0%
44.2%
15.2%
2.6%
0.1%
0.2%
1.2%
2.0%
1.8%
instructional media centre, Laboratories Branch – 2001
10.7%
Ontario
British Columbia
Quebec
Alberta
Manitoba
Nova Scotia
Saskatchewan
New Brunswick
Newfoundland
PEI
Hypothetical number of
HCV-infected persons in Canada
by mode of transmission
Mode of
transmission
Number at risk
HCV
prevalence
HCV
number
Transfusion
recipients
2,700,000
1.3%
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%
instructional media centre, Laboratories Branch – 2001
35,000
Proportion
(%)
Plausible limits
15%
(215,000 - 275,000)
Annual incidence of
HCV infection in Canada:
Preliminary perspectives
Method 1 Observed incidence among populations in
sentinel surveillance study projected from
proportion symptomatic to all HCV
infections
Method 2 Observed HCV incidence among
susceptible IDUs in study cohorts
projected from proportion IDU to all
HCV infections
(90,000 IDU - 68,000 HCV) x 20%
Preliminary estimate: 3,000 - 8,000 new
HCV infections per year
instructional media centre, Laboratories Branch – 2001
HCV infections in Canada:
Interpretation
 Estimates
are subject to considerable
uncertainty due to very limited Canadian data
from representative study populations
(only one study, in Quebec)
 HCV
prevalence appears highest in British
Columbia, Ontario and Alberta. Four provinces,
British Columbia, Ontario, Quebec and Alberta
account for ~92% of HCV infections in Canada
 The
majority (>50%) of prevalent HCV infections
in Canada are among IDUs, where HCV
prevalence is >100-fold greater than other
Canadians taken as a whole
instructional media centre, Laboratories Branch – 2001
Estimating the number of persons in
Canada with dual HCV-HIV infection:
Methods
1. Estimate the number of HIV-infected persons by HIVdefined exposure category and geographic region
2. Estimate HCV prevalence in each group (obtain data
from available studies and review by expert
consensus panel)
3. Multiply number by HCV prevalence
4. Plausible limits of outcome using Monte Carlo
simulation
5. Special analysis for Aboriginal population and
prisoners to estimate persons in each HIV-defined
exposure category and then as above
instructional media centre, Laboratories Branch – 2001
Modeled number of HCV-HIV infected
persons by exposure category, 1999
MSM
MSM-IDU
IDU
Endemic
Other
hetero
Clotting
factors
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
instructional media centre, Laboratories Branch – 2001
Modeled number of HCV-HIV infected
persons by exposure category, 1999
(n=11,194)
MSM
MSM-IDU
IDU
Endemic
Other hetero
Clottingfactors
Transfusion
71%
15%
11%
0.1%
instructional media centre, Laboratories Branch – 2001
0.6%
1.1%
2.1%
Modeled number of HCV-HIV infected
persons by geographic region, 1999
(n=11,194)
34%
Ontario
Quebec
British Columbia
Alberta
Prairies
Atlantic
Yukon / NWT
29%
25%
6.8%
1.0%
instructional media centre, Laboratories Branch – 2001
3.3%
1.7%
Modeled number of HCV-HIV
infected Aboriginal people
by exposure category, 1999
(n=1,477)
MSM
MSM-IDU
IDU
Other hetero
Clotting factors
Transfusion
87%
10%
0.9%
0.4%
0.2%
1.8%
instructional media centre, Laboratories Branch – 2001
Modeled number of HCV-HIV
infected prisoners
by exposure category, 1999
(n=611)
88%
MSM
MSM-IDU
IDU
Endemic
Other hetero
Clottingfactors
Transfusion
11%
0.6%
0.0%
instructional media centre, Laboratories Branch – 2001
0.0%
0.0%
0.9%
Conclusions
 Current
estimates of HCV infections must be
considered as hypotheses, not as conclusions;
the epidemiology of HCV infection in Canada
remains largely unknown.
 Population-based
studies are necessary
 Burden
of HCV infection is greatest in four provinces
which account for most HCV infections in Canada
 Most
new HCV infections are probably among IDUs
but a substantial proprtion, possibility as many as
40%, are not related to injection
 Transmission
of HCV (probability, determinants) in
other populations needs further elucidation
instructional media centre, Laboratories Branch – 2001