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The epidemiology of HIV infection among persons from HIV-endemic countries in Ontario. Robert S. Remis MD Department of Public Health Sciences University of Toronto Community Forum organized under the auspices of the HIV Endemic Task Force November 3, 2001 – Toronto, Ontario.
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The epidemiology of HIV infection among persons from HIV-endemic countries in Ontario Robert S. Remis MD Department of Public Health Sciences University of Toronto Community Forum organized under the auspices of the HIV Endemic Task Force November 3, 2001 – Toronto, Ontario
Acknowledgments • 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
Background • 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
Definition: HIV-Endemic • High prevalence of HIV infection in the general population (generally greater than 0.8% but may attain 20% or higher); • and • Heterosexual contact the most important mode of transmission;
Study 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
Methods • 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
Methods: Data sources Population Vital Statistics, Registrar General and Statistics Canada HIV 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, 044 Mother-infant HIV Canadian Pediatric AIDS Research Group Ontario region
Methods: Selection of countries Category 1: Modeled individuallyCategory 2: Modeled regionallyCategory 3: Not modeled Caribbean Category 1 6 Category 2 8 (1) Category 3 15 Africa Category 1 7 Category 2 17 (4) Category 3 20
Results: Population “Census” population Caribbean 256,000 African 94,000 Total 350,000However, 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
Results: 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)
Results: Descriptive 2 • Deaths 311 HIV-related deaths 67% residents of Toronto 73% Caribbean • Mother-infant HIV transmission 116 HIV-positive mother-infant pairs 62 HIV-infected infants 58% of infants overall but 70% in recent years 63% cared for in Toronto 76% among mothers from Africa
Results: HIV model • Model fit well for most countries • HIV-infected persons, 1998 Caribbean 1,491 African 855 Total 2,346 • HIV prevalence Caribbean 0.5% (0.4% - 3.8%) Africa 0.9% (0.6% - 4.5%)
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 infections Ethiopia 158 (19%) Somalia 138 (16%) South Africa 133 (16%) Uganda 96 (11%) Kenya 91 (11%)
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 1990 Caribbean 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
Modeled HIV prevalence among persons born in sub-Saharan Africa or Caribbean, Ontario 1981-98
Interpretation • 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%
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 Interpretation: Comparison with other groups
Comparison of HIV infection rates MSM 1:8 IDU 1:15 Endemic 1:140 Other heterosexual 1:4,400 Interpretation: Comparison with other groups
Summary 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