Trends in HIV incidence in Ontario based on the detuned assay: Update to October 2000 Robert S. Remis, Carol Major, Carol Swantee, Margaret Fearon, Evelyn Wallace, Elaine Whittingham Department of Public Health Sciences, University of Toronto HIV Laboratory, Laboratory Services, Ontario Ministry of Health and Long-Term Care Public Health Branch, Ontario Ministry of Health and Long-Term Care Canadian Association of HIV/AIDS Research 10th Annual Scientific Conference Toronto, Ontario, May 31-June 3, 2001

MOHLTC, Laboratories Branch, IMC – 2001 Acknowledgements At the HIV LaboratoryAt the HIV Laboratory Lisa Santangelo and Cindi Farina, data collectionLisa Santangelo and Cindi Farina, data collection Lynda Healey, detuned assayLynda Healey, detuned assay Elaine McFarlane, data entry screensElaine McFarlane, data entry screens Len Neglia, mailout of questionnairesLen Neglia, mailout of questionnaires Regional PHLs, mailout of questionnairesRegional PHLs, mailout of questionnaires Physicians who prescribe HIV testing, supplementary dataPhysicians who prescribe HIV testing, supplementary data Ontario HIV Treatment Network, fundingOntario HIV Treatment Network, funding

MOHLTC, Laboratories Branch, IMC – 2001 Introduction Serodiagnostic data may useful for surveillanceSerodiagnostic data may useful for surveillance However,However, persons who test may not be representativepersons who test may not be representative data quality inconsistentdata quality inconsistent True HIV incidence and HIV prevalence cannot be derived directly from dataTrue HIV incidence and HIV prevalence cannot be derived directly from data

MOHLTC, Laboratories Branch, IMC – 2001 Introduction Testing of HIV-positive specimens using less sensitive (“detuned”) assay permits the identification of persons who recently seroconverted (< 4 months)Testing of HIV-positive specimens using less sensitive (“detuned”) assay permits the identification of persons who recently seroconverted (< 4 months) Allows calculation of HIV incidence density, an important indicator usually difficult to measureAllows calculation of HIV incidence density, an important indicator usually difficult to measure

MOHLTC, Laboratories Branch, IMC – 2001 Study objectives To accurately determine the number of persons newly testing positive for HIVTo accurately determine the number of persons newly testing positive for HIV To determine the distribution of exposure category among newly diagnosed HIV-infected personsTo determine the distribution of exposure category among newly diagnosed HIV-infected persons To estimate HIV incidence density among persons undergoing HIV testingTo estimate HIV incidence density among persons undergoing HIV testing

MOHLTC, Laboratories Branch, IMC – 2001 Data collection and management Questionnaire sent with HIV-positive resultsQuestionnaire sent with HIV-positive results and 1:200 sample of HIV-negative results Data on risk factors for HIV infection and HIV test historyData on risk factors for HIV infection and HIV test history Questionnaire may be returnedQuestionnaire may be returned by mail or faxby mail or fax by telephone interviewby telephone interview Data entered in Microsoft AccessData entered in Microsoft Access

MOHLTC, Laboratories Branch, IMC – 2001 Laboratory methods Abbott 3A11 EIA kit modified as follows:Abbott 3A11 EIA kit modified as follows: serum diluted to 1:20,000serum diluted to 1:20,000 incubation period reduced to 30 minutesincubation period reduced to 30 minutes cut-off value increasedcut-off value increased

MOHLTC, Laboratories Branch, IMC – 2001 Study questionnaires mailed and returned, Oct 1999 to Dec 2000 Questionnaires Kaplan - Meier returned by MailedReturnedProportion 4 mon. 8 mon. HIV-positiveHIV-negativeTotal1,0711,3922, ,0011,73468%72%70%72%73%79%80%

MOHLTC, Laboratories Branch, IMC – 2001 Exposure category classification according to HIV test requisition, returned questionnaires and modeled distribution, HIV-positives HIV test requisition Returned questionnaires of NIR Projected final distribution MSMMSM-IDUIDUEndemic HR hetero LR hetero OtherNIR %3%13%6%6%15%2% %2%10%21%7%21%1% %2%11%14%6%18%2% Total1, %1,071100% %NIR49%42%

MOHLTC, Laboratories Branch, IMC – 2001 HIV-negatives HIV test requisition Returned questionnaires of NIR Projected final distribution MSMMSM-IDUIDUEndemic HR hetero LR hetero OtherNIR %1%5%1%7%70%8% %0%4%4%4%82%3% ,072715%0%5%2%6%77%5% Total1, ,392100% %NIR59%39%

MOHLTC, Laboratories Branch, IMC – 2001 Previous testing history among "first-time" positive diagnoses Previously tested in: Previous test result Total PositiveNegative OntarioOther Total No previous test Total "first-time" positives 1,071.0 Proportion of “first-time” positives who have had a previous positive in Ontario 8.9%

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence (per 100 person-years) for selected exposure categories by health region TorontoOttawa Rest of Ontario Overall TestedIncidenceTestedIncidenceTestedIncidenceTestedIncidence MSMMSM-IDUIDU HR hetero LR hetero 6, ,7254,91678, , ,1931,70623, , ,0356,644110, , ,95313,265212,

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence for selected exposure categories by health region

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence (per 100 person-years) among IDU, by health region and sex

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence (per 100 person-years) among HR heterosexuals, by health region and sex

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence by quarter, MSM

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence by quarter, MSM-IDU

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence by quarter, IDU

MOHLTC, Laboratories Branch, IMC – 2001 HIV incidence by age group, selected exposure categories

MOHLTC, Laboratories Branch, IMC – 2001 Summary of findings Exposure category distribution among thoseExposure category distribution among those with risk factor data not representative ~9% of persons with an apparent first HIV-positive test were previously tested in Ontario~9% of persons with an apparent first HIV-positive test were previously tested in Ontario Trends in HIV incidenceTrends in HIV incidence MSM: highest in Toronto but decreasing;MSM: highest in Toronto but decreasing; low and stable in Ottawa; intermediate elsewhere but increasing IDU: high in Ottawa; lower elsewhereIDU: high in Ottawa; lower elsewhere Incidence apparently not higher in younger personsIncidence apparently not higher in younger persons

MOHLTC, Laboratories Branch, IMC – 2001 Interpretation Number of discordant samples and HIV tests by exposure category modeledNumber of discordant samples and HIV tests by exposure category modeled Interpretation of HIV incidence must incorporate knowledge of patterns in HIV test seeking behavioursInterpretation of HIV incidence must incorporate knowledge of patterns in HIV test seeking behaviours Observed HIV incidence likely higher than for populationObserved HIV incidence likely higher than for population

MOHLTC, Laboratories Branch, IMC – 2001 Conclusions HIV serodiagnostic program extremely useful for HIV surveillanceHIV serodiagnostic program extremely useful for HIV surveillance Due to important problems in missing and unrepresentative data on risk factors and HIV test history, available data must be enhanced through supplementary means on an ongoing basisDue to important problems in missing and unrepresentative data on risk factors and HIV test history, available data must be enhanced through supplementary means on an ongoing basis Detuned assay provides a critical indicator of trends in the epidemic at low costDetuned assay provides a critical indicator of trends in the epidemic at low cost