Laboratories Branch, MOHLTC, IMC – 2001
Estimates and projections of Estimates and projections of HIV infection among persons from HIV infection among persons from HIVHIV--endemic countries in Ontarioendemic countries in Ontario
Robert S. Remis MDDepartment of Public Health Sciences University of Toronto
ACCHO Research SummitApril 28, 2006, Toronto, Ontario
Laboratories Branch, MOHLTC, IMC – 2001
BackgroundBackground
• 1990-98: Anecdotal case reports and growing community concern
• Limited research and few data• HIV Endemic Task Force mandated an
epidemiologic assessment in November 1998• Completed in 1999; updated in 2003
Laboratories Branch, MOHLTC, IMC – 2001
Definition: HIVDefinition: HIV--endemicendemic
1. HIV prevalence in the general population >1% (may be 20% or more)
and 1. Heterosexual contact most important (>50%)
mode of transmission
Laboratories Branch, MOHLTC, IMC – 2001
Study mandateStudy mandate
• Characterize the incidence and prevalence of HIV infection among persons from HIV-endemic countries in Ontario
Laboratories Branch, MOHLTC, IMC – 2001
Methods: Model structureMethods: Model structure
Stage 1: Demographic modelEstimate population by sex and country of birth(and region of residence) from 1981 to 2002
Stage 2: HIV infection modelEstimate prevalence of HIV infection by sex andcountry of birth from 1981 to 2002
Laboratories Branch, MOHLTC, IMC – 2001
Methods: Model structureMethods: Model structure
Fitting model
• Model outputs compared to observed data (targets): AIDS incidence, AIDS-related deaths and HIV-infected mothers and infants
• HIV prevalence immigration factor adjusted to minimize the Goodness-of-fit statistic
Laboratories Branch, MOHLTC, IMC – 2001
Methods: Selection of countriesMethods: Selection of countries
• Category 1: Individual modelCountries with large population in Ontario or large number of AIDS cases
• Category 2: RegionalCountries with few immigrants in Ontario and few AIDS cases
• Category 3: Excluded
Laboratories Branch, MOHLTC, IMC – 2001
Methods: Selection of countriesMethods: Selection of countries
Caribbean Category 1 6Category 2 8 (as one group)Category 3 15
Africa Category 1 7Category 2 17 (as four groups)Category 3 20
Laboratories Branch, MOHLTC, IMC – 2001
Results: PopulationResults: Population
“Census” population: Caribbean 264,300African 99,600Total 363,900
• Modeled population (includes 2nd generation):
Caribbean 406,900 African 156,500 Total 563,400
Laboratories Branch, MOHLTC, IMC – 2001
Results: Data sourcesResults: Data sources
• HIV Adjusted HIV diagnoses: 2,071 (8.8%) among 21,453 HIV diagnoses in Ontario but 22% in 2001 and 2002 compared to 6.7% in 1985-1998
• AIDS 376 cases (5.1%) among 6,952 AIDS cases reported in Ontario but 20% in 2001 and 2002 compared to 4.6% in 1981-2000
Laboratories Branch, MOHLTC, IMC – 2001
Results: HIV modelResults: HIV model
• Model fit well for most countries
• HIV-infected persons, 2002 Caribbean 1,366African 1,261Total 2,627
• HIV prevalence Caribbean 0.5% (0.3% - 2.9%)Africa 1.1% (0.5% - 10.1%)
Laboratories Branch, MOHLTC, IMC – 2001
Results: HIV model (contResults: HIV model (cont’’d)d)
• Caribbean: Four countries [86% of HIV infections]Jamaica 494 (36%)Trinidad 277 (20%)Guyana 261 (19%)Haiti 147 (11%)
• Africa: Five countries [66% of HIV infections]Ethiopia 366 (29%)Uganda 131 (10%)Somalia 127 (10%)South Africa 114 ( 9%)Kenya 88 ( 7%)
Laboratories Branch, MOHLTC, IMC – 2001
Results: HIV model (contResults: HIV model (cont’’d) d)
• Substantial HIV transmission in Canada, representing 22-59% of HIV infections
• Male: female ratios indicate importance of MSM, especially from Caribbean
• Marked increase in recent years • Annual increase of about 270 HIV infections, or about
12%, in latest year
Laboratories Branch, MOHLTC, IMC – 2001
Modeled HIV prevalence among persons born in Modeled HIV prevalence among persons born in subsub--Saharan Africa or Caribbean, Ontario, 1981Saharan Africa or Caribbean, Ontario, 1981--20022002
0
200
400
600
800
1,000
1,200
1,400
1,600
1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001
Year
Num
ber
of H
IV-in
fect
ed p
erso
ns
Sub-Saharan AfricaCaribbean
Laboratories Branch, MOHLTC, IMC – 2001
Modeled number of imported and newly Modeled number of imported and newly acquired HIV infections among persons acquired HIV infections among persons born in HIVborn in HIV--endemic countries, 1992endemic countries, 1992--20022002
0
50
100
150
200
250
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002Year
Num
ber
of H
IV-in
fect
ed p
erso
ns
ImportedAcquired
Laboratories Branch, MOHLTC, IMC – 2001
Modeled and projected number of HIV infections Modeled and projected number of HIV infections among persons born in HIVamong persons born in HIV--endemic countries, endemic countries, Ontario, 1992Ontario, 1992--20122012
0
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 2012Year
Num
ber
of H
IV-in
fect
ed p
erso
ns
ModeledProjected
Laboratories Branch, MOHLTC, IMC – 2001
InterpretationInterpretation
• Estimates based on modeling • Therefore estimates not precise; represent rather a
“plausible range”• Some parameters had to be adjusted, adding
uncertainty to the results • Level of uncertainty not known but probably ~30%
Laboratories Branch, MOHLTC, IMC – 2001
Interpretation: Interpretation: Comparison with other groupsComparison with other groups
• Low compared to other highly affected groups • Compared to other heterosexual persons in Ontario
• 15-fold higher for persons from Caribbean• 30-fold higher for persons from sub-Saharan Africa
HIV prevalence HIV numberProportion infections
HIV-endemicMSMIDUOther hetero
~0.7%10-15%5-10%
~0.03%
2,60013,6001,9003,100
12%64%9%
15%
Laboratories Branch, MOHLTC, IMC – 2001
Interpretation: Interpretation: Comparison with other groupsComparison with other groups
• Comparison of HIV infection rates• MSM 1:8• IDU 1:15• Endemic 1:140• Other heterosexual 1:3,000
Laboratories Branch, MOHLTC, IMC – 2001
Summary of findingsSummary of findings
• Modeling yielded plausible estimates for 2002:2,630 HIV-infected persons Caribbean 1,260 & sub-Saharan Africa 1,370
• Estimates constitute an hypothesis; studies needed to confirm findings
• HIV prevalence increasing substantially each year• Fitted projected model corresponds closely to
estimates for 2004 (3,300)• Despite uncertainty, HIV prevalence expected to
double from 2004 to 2011 (annual increase >10%)• In 2002, 59% of HIV infections acquired here
Laboratories Branch, MOHLTC, IMC – 2001
AcknowledgmentsAcknowledgments
• Maraki Fikre Merid and Elaine Whittingham, Public Health Sciences, University of Toronto
• Frank McGee, AIDS Bureau, Ontario Ministry of Health and Long-Term Care (OMHLTC)
• HIV Endemic Task Force / ACCHO