Trends in HIV incidence in Trends in HIV incidence in Ontario based on the detuned Ontario based on the detuned assay: Update to October 2000 assay: Update to October 2000 Robert S. Remis, Carol Major, Carol Swantee, Robert S. Remis, Carol Major, Carol Swantee, Margaret Fearon, Evelyn Wallace, Elaine Margaret Fearon, Evelyn Wallace, Elaine Whittingham Whittingham Department of Public Health Sciences, University of Toronto Department of Public Health Sciences, University of Toronto HIV Laboratory, Laboratory Services, HIV Laboratory, Laboratory Services, Ontario Ministry of Health and Long-Term Care Ontario Ministry of Health and Long-Term Care Public Health Branch, Public Health Branch, Ontario Ministry of Health and Long-Term Care Ontario Ministry of Health and Long-Term Care Canadian Association of HIV/AIDS Research Canadian Association of HIV/AIDS Research 10th Annual Scientific Conference 10th Annual Scientific Conference Toronto, Ontario, May 31-June 3, 2001 Toronto, Ontario, May 31-June 3, 2001
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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.
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Trends in HIV incidence in Trends in HIV incidence in Ontario based on the Ontario based on the detuned assay: Update to detuned assay: Update to October 2000October 2000
Robert S. Remis, Carol Major, Carol Swantee, Robert S. Remis, Carol Major, Carol Swantee, Margaret Fearon, Evelyn Wallace, Elaine Margaret Fearon, Evelyn Wallace, Elaine WhittinghamWhittinghamDepartment of Public Health Sciences, University of TorontoDepartment of Public Health Sciences, University of Toronto
HIV Laboratory, Laboratory Services, HIV Laboratory, Laboratory Services, Ontario Ministry of Health and Long-Term CareOntario Ministry of Health and Long-Term Care
Public Health Branch, Public Health Branch, Ontario Ministry of Health and Long-Term CareOntario Ministry of Health and Long-Term Care
Canadian Association of HIV/AIDS ResearchCanadian Association of HIV/AIDS Research10th Annual Scientific Conference10th Annual Scientific ConferenceToronto, Ontario, May 31-June 3, 2001Toronto, Ontario, May 31-June 3, 2001
MOHLTC, Laboratories Branch, IMC – 2001
AcknowledgementsAcknowledgements• At the HIV LaboratoryAt the HIV Laboratory
• Lisa Santangelo and Cindi Farina, data Lisa Santangelo and Cindi Farina, data collectioncollection
• Lynda Healey, detuned assayLynda Healey, detuned assay• Elaine McFarlane, data entry screens Elaine 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, Physicians who prescribe HIV testing,
supplementary datasupplementary data• Ontario HIV Treatment Network, fundingOntario HIV Treatment Network, funding
MOHLTC, Laboratories Branch, IMC – 2001
IntroductionIntroduction• Serodiagnostic data may useful for Serodiagnostic data may useful for
surveillancesurveillance• 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 True HIV incidence and HIV prevalence cannot
be derived directly from databe derived directly from data
MOHLTC, Laboratories Branch, IMC – 2001
IntroductionIntroduction• Testing of HIV-positive specimens using Testing of HIV-positive specimens using
less sensitive (“detuned”) assay permits less sensitive (“detuned”) assay permits the identification of persons who recently the identification of persons who recently seroconverted (< 4 months) seroconverted (< 4 months)
• Allows calculation of HIV incidence density, an Allows calculation of HIV incidence density, an important indicator usually difficult to important indicator usually difficult to measuremeasure
MOHLTC, Laboratories Branch, IMC – 2001
Study objectivesStudy objectives• To accurately determine the number of To accurately determine the number of
persons newly testing positive for HIV persons newly testing positive for HIV • To determine the distribution of exposure To determine the distribution of exposure
category among newly diagnosed HIV-category among newly diagnosed HIV-infected personsinfected persons
• To estimate HIV incidence density among To estimate HIV incidence density among persons undergoing HIV testing persons undergoing HIV testing
MOHLTC, Laboratories Branch, IMC – 2001
Data collection and managementData collection and management• Questionnaire sent with HIV-positive results Questionnaire sent with HIV-positive results
and 1:200 sample of HIV-negative resultsand 1:200 sample of HIV-negative results• Data on risk factors for HIV infection and Data on risk factors for HIV infection and
HIV test historyHIV 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 methodsLaboratory 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 increased cut-off value increased
MOHLTC, Laboratories Branch, IMC – 2001
Study questionnaires mailed and Study questionnaires mailed and returned, Oct 1999 to Dec 2000returned, Oct 1999 to Dec 2000
Exposure category classification according Exposure category classification according to to HIV test requisition, returned questionnaires HIV test requisition, returned questionnaires and modeled distribution, HIV-positives and modeled distribution, HIV-positives
Previous testing history among Previous testing history among "first-time" positive diagnoses"first-time" positive diagnoses
PreviouslyPreviouslytested in:tested in:
Previous test resultPrevious test result
TotalTotalPositivePositive NegativeNegative
OntarioOntario
OtherOther
95.195.1
91.3 91.3
373.5 373.5
68.2 68.2
468.6 468.6
159.5 159.5
TotalTotal 186.4 186.4 441.7 441.7 628.1 628.1
No previous testNo previous test 442.9442.9
Total "first-time" positivesTotal "first-time" positives 1,071.01,071.0
Proportion of “first-time” positives who Proportion of “first-time” positives who have had a previous positive in Ontario have had a previous positive in Ontario 8.9%8.9%
MOHLTC, Laboratories Branch, IMC – 2001
HIV incidence (per 100 person-HIV incidence (per 100 person-years) for selected exposure years) for selected exposure categories by health regioncategories by health region
TorontoToronto OttawaOttawa Rest of OntarioRest of Ontario OverallOverall
HIV incidence (per 100 person-HIV incidence (per 100 person-years) among HR heterosexuals, years) among HR heterosexuals, by health region and sexby health region and sex
Males Females Overall
ID (95% CI) ID (95% CI) ID (95% CI)
Toronto 0.05 (0.0, 0.73) 0.25 (0.08, 0.75) 0.18 (0.06, 0.52)
HIV incidence by quarter, MSMHIV incidence by quarter, MSM
0.0
1.0
2.0
3.0
4.0
5.0
6.0
1999-Q4 2000-Q1 2000-Q2 2000-Q3
Quarter
HIV
inci
dence
(per
100 p
y)
TorontoOttawaRest of Ontario
MOHLTC, Laboratories Branch, IMC – 2001
HIV incidence by quarter, MSM-IDUHIV incidence by quarter, MSM-IDU
0
5
10
15
20
25
30
35
40
1999-Q4 2000-Q1 2000-Q2 2000-Q3
Quarter
HIV
inci
dence
(per
100 p
y) TorontoOttawa
Rest of Ontario
MOHLTC, Laboratories Branch, IMC – 2001
HIV incidence by quarter, IDU HIV incidence by quarter, IDU
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
1999-Q4 2000-Q1 2000-Q2 2000-Q3
Quarter
HIV
inci
dence
(per
100 p
y)
Toronto
OttawaRest of Ontario
MOHLTC, Laboratories Branch, IMC – 2001
HIV incidence by age group, HIV incidence by age group, selected exposure categoriesselected exposure categories
0.0
1.0
2.0
3.0
4.0
5.0
6.0
15-24 25-29 30-34 35-39 40-44 45-49 50+
Age Group
HIV
inci
dence
(p
er
100 p
y)
MSMIDULR hetero
MOHLTC, Laboratories Branch, IMC – 2001
Summary of findingsSummary of findings• Exposure category distribution among those Exposure category distribution among those
with risk factor data not representative with risk factor data not representative • ~9% of persons with an apparent first HIV-~9% of persons with an apparent first HIV-
positive test were previously tested in Ontariopositive test were previously tested in Ontario• Trends in HIV incidence Trends in HIV incidence
• MSM: highest in Toronto but decreasing; MSM: highest in Toronto but decreasing; low and stable in Ottawa; intermediate low and stable in Ottawa; intermediate elsewhere but increasingelsewhere but increasing
• IDU: high in Ottawa; lower elsewhereIDU: high in Ottawa; lower elsewhere• Incidence apparently not higher in younger Incidence apparently not higher in younger
personspersons
MOHLTC, Laboratories Branch, IMC – 2001
InterpretationInterpretation
• Number of discordant samples and HIV tests Number of discordant samples and HIV tests by exposure category modeled by exposure category modeled
• Interpretation of HIV incidence must Interpretation of HIV incidence must incorporate knowledge of patterns in HIV test incorporate knowledge of patterns in HIV test seeking behavioursseeking behaviours
• Observed HIV incidence likely higher than for Observed HIV incidence likely higher than for population population
MOHLTC, Laboratories Branch, IMC – 2001
ConclusionsConclusions
• HIV serodiagnostic program extremely useful HIV serodiagnostic program extremely useful for HIV surveillance for HIV surveillance
• Due to important problems in missing and Due to important problems in missing and unrepresentative data on risk factors and HIV unrepresentative data on risk factors and HIV test history, available data must be enhanced test history, available data must be enhanced through supplementary means on an ongoing through supplementary means on an ongoing basisbasis
• Detuned assay provides a critical indicator of Detuned assay provides a critical indicator of trends in the epidemic at low costtrends in the epidemic at low cost