HIV Prevalence Among ANC Attending Women Ethiopia, 1995-2003 . Previous studies have shown that age-specific changes in HIV prevalence can be used to estimate the incidence of HIV infection Young age (15-24 yrs) as proxy for recent infection in HIV prevalence surveys has been used to estimate HIV incidence.
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1. Consensus Meeting for Improving the Quality of Laboratory Testing for HIV Surveillance Temporal Trends in the Incidence of HIV Infection in Addis Ababa, 1995 to 2003 Dawit Wolday, MD, PhD EHNRI/CDC Programme on HIV/STI & TB Ethiopian Health and Nutrition Research Institute Addis Ababa, Ethiopia
3. Previous studies have shown that age-specific changes in HIV prevalence can be used to estimate the incidence of HIV infection
Young age (15-24 yrs) as proxy for recent infection in HIV prevalence surveys has been used to estimate HIV incidence Background
5. Do the declines noted in HIV prevalence, especially among young age groups, indicate also declines in new infections?
6. Training at CDC-Atlanta Lab
Validation of BED incidence assay for HIV subtype C infection using panel of seroconverters sera with known dates of seroconvertion
Transfer of the assay to EHNRI
Use of BED assay for cross-sectional ANC samples from A.A.
In future…for all samples available for QC
Implementation of the incidence assay in Ethiopia: the steps
8. To estimate the trend in the incidence of HIV infection among women attending ANC in Addis Ababa between 1995 to 2003 using BED-CEIA incidence assay
To compare the BED assay with age-specific incidence estimates derived from age-specific prevalence surveys
[To compare the BED assay with models that estimate incidence]
Objectives of the Study
9. Annual ANC-based seroprevalence surveys were conducted between 1995 and 2003 in Addis Ababa, Ethiopia
About 300-350 consecutive samples were tested per site; 2 sites in 1995 and 4 sites from 1996 onwards; 5 sites in 2003
Samples collected from ANC sites were transported to ENARP/EHNRI laboratory and stored at -80oC; for 2003 samples were from QC Study Population
10. SEROPREVALENCE SURVEY:
HIV testing was done by EIA
Algorithm: Vironostika, if+ re-testing by Murex, WB for discordant
Syphilis testing was done by RPR & TPHA/TPPA
Participates in the CDC-MPEP, 2x/year
All HIV positive samples were retrieved, thawed and tested with BED-CEIA incidence assay
Specimens with a calculated standard OD (sample OD-negative control OD) of < 1.200 were retested in triplicate
Retested specimens that had a mean standard OD of < 0.800 were considered as recent Laboratory investigations
11. Incidence rate calculation
12. Temporal trends in demographic characteristics of women attending ANC 1995-2003 Addis Ababa, Ethiopia
16. Changes in A.A. surveillance [prevalence]
Sites increased to 5
Decentralized – work transferred to A.A. Regional Lab
QC at NRLA: 10 samples reported as negative by the AARL were found to be positive
17. The overall prevalence declined from 21% in 1995 to 12% in 2003
The prevalence of HIV declined significantly among young women aged 15 to 24 years between 1995 and 2003; no decline was noted for older ages
Decline in the prevalence of HIV is supported by decline in the overall incidence as well as in the younger age group
18. BED-CEIA incidence assay can be used to provide rapid and relatively inexpensive estimates of incidence, which are urgently needed for various programmes
Need for further evaluation of the assay in other countries
19. EHNRI Staff
Bharat S. Parekh
20. Thank you!!