Estimates and projections of HIV infection among persons ... plus.pdf · HIV infection among persons from HIV-endemic countries in Ontario Robert S. Remis MD Department of Public

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