Laboratories Branch, MOHLTC, IMC – 2001

The epidemiology of The epidemiology of HIV infection among HIV infection among

persons from HIV-endemic persons from HIV-endemic countries countries in Ontarioin Ontario

Robert S. Remis MDDepartment of Public Health Sciences University of

TorontoCommunity Forum

organized under the auspices of the HIV Endemic Task Force

November 3, 2001 – Toronto, Ontario

Laboratories Branch, MOHLTC, IMC – 2001

AcknowledgmentsAcknowledgments

•Elaine Whittingham, Department of Public Health Sciences, University of Toronto

•Frank McGee, AIDS Bureau, Ontario Ministry of Health and Long-Term Care (OMHLTC)

•Carol Major, HIV Laboratory, OMHLTC•Dr. Evelyn Wallace, Public Health Branch, OMHLTC•Vital Statistics Division, Registrar-General of

Ontario•Dr. Susan King, Hospital for Sick Children•HIV Endemic Task Force

Laboratories Branch, MOHLTC, IMC – 2001

BackgroundBackground

•Anecdotal reports, especially from the Hospital for Sick Children, Toronto

•Growing community concern•Limited research and few specific data

available•Formation of HIV Endemic Task Force

Laboratories Branch, MOHLTC, IMC – 2001

Definition: HIV-EndemicDefinition: HIV-Endemic

1. High prevalence of HIV infection in the general population (generally greater than 0.8% but may attain 20% or higher);

2. and 3. Heterosexual contact the most important

mode of transmission;

Laboratories Branch, MOHLTC, IMC – 2001

Study mandateStudy mandate

•Describe population born in HIV-endemic countries stratified by region of residence and country of origin

•Characterize incidence and prevalence of HIV infection among persons from HIV-endemic countries

Laboratories Branch, MOHLTC, IMC – 2001

MethodsMethods

•Two stages•Estimate population by gender, region of

residence and country of birth (‘demographic model’ based on immigration, births, deaths, and census estimates),

•Estimate prevalence of HIV infection

•Spreadsheet model•Multiple data sources•Derive estimates which best ‘fit’ the observed

dataLimitations of modeling approach

Laboratories Branch, MOHLTC, IMC – 2001

Methods: Data sourcesMethods: Data sources

Population Vital Statistics, Registrar General

and Statistics CanadaHIV diagnostic data HIV Laboratory:

HIV-positive diagnoses from 1985 to 1998

Reported AIDS cases AIDS Surveillance Program, Public Health Branch: cases reported from 1981 to 1998

HIV mortality Vital Statistics, Registrar General

Deaths with codes 042, 043, 044Mother-infant HIV Canadian Pediatric AIDS

Research Group Ontario region

Laboratories Branch, MOHLTC, IMC – 2001

Methods: Selection of countriesMethods: Selection of countries

Category 1: Modeled individuallyCategory 2: Modeled regionallyCategory 3: Not modeled

Caribbean Category 1 6Category 2 8 (1)Category 3 15

Africa Category 1 7Category 2 17 (4)Category 3 20 

Laboratories Branch, MOHLTC, IMC – 2001

Results: PopulationResults: Population

“Census” population Caribbean 256,000African 94,000Total 350,000

 However, modeled population is Caribbean 371,000 and African 120,000 for a total of 491,000 (includes second generation) Toronto: Caribbean (86%) and African (76%);

overall 84% Ottawa: 6% overall, but 74% of Haitians and

29% of Somalians

Laboratories Branch, MOHLTC, IMC – 2001

Results: Descriptive 1Results: Descriptive 1

•HIV Adjusted HIV diagnoses: 1,350

•AIDS 258 cases (4.0%) among 6,502 AIDS cases reported in Ontario but 9%, 12% and

17% of cases in 1996, 1997 and 1998, respectively

61% of cases from Caribbean

Substantial number (151) MSM-endemic cases not evident in classification using hierarchy

Male:female ratios high for Caribbean cases (7.9)

compared to Africa (2.5)

Laboratories Branch, MOHLTC, IMC – 2001

Results: Descriptive 2Results: Descriptive 2

•Deaths 311 HIV-related deaths 67% residents of Toronto

73% Caribbean

•Mother-infant HIV transmission116 HIV-positive mother-infant pairs62 HIV-infected infants58% of infants overall but 70% in

recent years63% cared for in Toronto76% among mothers from Africa

Laboratories Branch, MOHLTC, IMC – 2001

Results: HIV modelResults: HIV model

•Model fit well for most countries

•HIV-infected persons, 1998 Caribbean 1,491African 855

Total 2,346

•HIV prevalence Caribbean 0.5% (0.4% - 3.8%) Africa 0.9% (0.6% - 4.5%)

Laboratories Branch, MOHLTC, IMC – 2001

Results: HIV model (cont’d)Results: HIV model (cont’d)

•Caribbean: Four countries account for 87% of infections

Jamaica 544 (36%)Guyana 311 (21%)Trinidad 295 (20%)Haiti 142 (10%)

•Africa: Five countries account for 72% of infectionsEthiopia 158 (19%)Somalia 138 (16%)South Africa 133 (16%)Uganda 96 (11%)Kenya 91 (11%)

Laboratories Branch, MOHLTC, IMC – 2001

Results: HIV model (cont’d) Results: HIV model (cont’d)

• Substantial HIV transmission in Canada, representing 30-45%of HIV infections

• Male: female ratios indicate importance of MSM-endemic,especially from Caribbean

• Marked increase in recent years, mostly since 1990 (especially for Africans)HIV prevalence in 1990Caribbean 370 (1998/1990 = 4.0)

African 150 (1998/1990 = 5.7)Total 520 (1998/1990 = 4.5)

 Annual increase of about 250 HIV infections, or about 12% in latest year

Laboratories Branch, MOHLTC, IMC – 2001

Modeled HIV prevalence among persons born Modeled HIV prevalence among persons born in in sub-Saharan Africa or Caribbean, Ontario sub-Saharan Africa or Caribbean, Ontario 1981-981981-98

0

200

400

600

800

1000

1200

1400

1600

1981 1983 1985 1987 1989 1991 1993 1995 1997

Year

Nu

mb

er o

f H

IV-i

nfe

cted

per

son

s

Sub-Saharan Africa

Caribbean

Laboratories Branch, MOHLTC, IMC – 2001

InterpretationInterpretation

•Estimates are based on modeling •Therefore, estimates are not precise but

represent plausible range•Also, data used often had to be adjusted, adding

additional uncertainty•Level of uncertainty not known exactly, but

probably about 30%

Laboratories Branch, MOHLTC, IMC – 2001

Interpretation: Interpretation: Comparison with other groupsComparison with other groups

•  Low compared to primarily affected groups •Compared to other heterosexual persons in Ontario,

•20-fold higher for persons from Caribbean•40-fold higher for persons from sub-Saharan Africa

HIV prevalence

HIV number

Proportion infections

EndemicMSMIDUOther hetero

~0.7%10-15%

5-10%~0.02%

2,60012,800

2,0002,400

12%61%

9%11%

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 1:4,400

Laboratories Branch, MOHLTC, IMC – 2001

Summary of findingsSummary of findings

•Modeling exercise produced plausible estimates of 2,350 HIV-infected persons Caribbean 1,500; sub-Saharan Africa 850

•HIV infection among persons from HIV-endemic countries is: •Lower than in persons living in country of origin•Lower than MSM and IDU•Higher than other heterosexual persons in

Ontario•Number of HIV infections increasing substantially

year over year•Estimates must be considered hypothesis:

Actual studies required to confirm findings