ias 2011, rome, july 17 - 20
DESCRIPTION
Generic protocol for national population-based impact evaluation of national programs for PMTCT at 6 weeks post-partum Thu-Ha Dinh, MD., MS., US CDC/GAP. IAS 2011, Rome, July 17 - 20. Overview of Presentation. Background -- Justification of the evaluation Evaluation questions - PowerPoint PPT PresentationTRANSCRIPT
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Generic protocol for national population-based impact evaluation of national programs for
PMTCT at 6 weeks post-partum
Thu-Ha Dinh, MD., MS., US CDC/GAP
IAS 2011, Rome, July 17 - 20
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Overview of Presentation• Background -- Justification of the evaluation• Evaluation questions • Primary objectives• Who – Where – How• Ethical consideration• Methods
• Design• Sample size• Testing algorithms
• Procedure• Data management – storage – analysis• Dissemination of findings
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PMTCT effectiveness• HIV transmission – proximate purpose of
programs is to reduce MTCT of HIV• ARV prophylaxis • Safe feeding• Maternal ART
• HIV free survival – ultimate goal of programs is to save children from HIV & death
• Time points: – Perinatal and during breast-feeding (6 wks, 6
months, 9 months, 12 months, 18 months, etc)
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Why do we need national population estimate?
• Overall effectiveness of the program• Assess mother-infant pairs in PMTCT and not
reached • Provide unbiased estimate of HIV-infected
infants/children
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Primary Evaluation Question• What is population-based perinatal MTCT rate measured
at 6 weeks? What is the HIV exposure prevalence among infants at 6 weeks ? What is the HIV infection prevalence among infants, 6 weeks What is the coverage of each PMTCT service along PMTCT cascade?
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How we measure HIV exposure prevalence?• Self-reported HIV positive status from mother?
– Self-report bias– HCT uptake
• Documented HIV positive status of mother during pregnancy?– Information documented – HCT uptake
• Identify maternal HIV antibody in targeted infant (biomedical marker) ? – No bias: self-report or HCT uptake or information doc.– Include HIV acquisition– Sensitivity and specificity of the antibody test used
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0-1 m 1-2 m 2-6 m 6-9 m 9-12 m 12-18 m
Maternal HIV ABHIV DNAinf_HIV Ab
Blood sample of HIV-infected in-fant
Thanks to Elaine Abrams and Nigel Rollinsx
Identify maternal HIV antibody in Infant
HIV
Ab
test
Thanks to E. Abram and N. Rollins
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Where we can recruit representative sample of the infant population?
• At labor and delivery clinic?– Home delivery?– HCT during ANC, L&D
• At home – household survey?• HCT during ANC, L&D– Not part of routine - expensive
• At immunization clinic?– The 1st immunization coverage >80%– The 1st immunization coverage 70% - 80% special
sample size and sub-study will be required to adjust for findings
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Design an Evaluation
• Questions objectives variables needed• Who: inclusion and exclusion, age range (4-8, 6-8?)• Where: to recruit potential participants • Ethical consideration• Design
– Cross-sectional design point estimate (6 weeks)– Sampling frame:
• multistage (province, facility) select facilities• participants from each selected facility (potential participant
load systematic or random or consecutive)
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Design: Sample size
• Estimate HIV prevalence in pregnant women• Estimate ARV uptake among HIV+ pregnant women• Estimate/collect existing MTCT • Specify the appropriate level of precision• Assume a design effect of 2 and double the
calculated sample size to take account of cluster sampling
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Design: Procedure
Eligible caregiver-infants
Do consent to take part in the survey
Don't consent to take part in the survey
Caregiver interview and infant-DBS
Caregiver interview and no infant-DBS
HIV DNA PCR positive(HIV-infected infant)
HIV DNA PCR negative (HIV uninfected infant)
HIV Ab Negative(HIV-unexposed infant)
HIV Ab positive(HIV-exposed infant)
Standard of care recommended
by WHO
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Consent and interview processcaregivers vs. mothers
Decision needs to be based on• Local situation all legal caregivers
– Orphan population – Proportion of mothers who work– Local child Act toward health care right/assess – Community consent acceptable ?
• Precision needed for estimate• Infant benefit vs. Mother benefit• Who should receive test result? ? validity of findings if caregivers excluded
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Design: Data management/Storage/Analysis • Data management:
– Quality control: at facility and at survey office– Data entry and safety– Who can access to the data – Ownership of the data
• Storage:– Paper-based: when paper-based will be destroyed– Public domain: how and when
• Data analysis– Dummy tables key outcomes – Identify potential bias can be controlled by analysis
collect those variables
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Dissemination of findings
• Provide feedback to clinics and provinces to improve/scale up program
• Provide feedback to provincial DOH and national MOH
• Share findings and lessons learned with other donors and organizations
• Publish findings on peer review journals