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Major Sutchana Tabprasit Armed Forces Research Institute of Medical Sciences (AFRIMS),

Recent Trends in estimated HIV-1 Incidence among Royal Thai Army (RTA) conscripts from 2005-2009 in Thailand. Major Sutchana Tabprasit Armed Forces Research Institute of Medical Sciences (AFRIMS), Royal Thai Army (RTA), Bangkok, Thailand. Primary HIV-1 Infection. Acute infection

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Major Sutchana Tabprasit Armed Forces Research Institute of Medical Sciences (AFRIMS),

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  1. Recent Trends in estimated HIV-1 Incidence among Royal Thai Army (RTA) conscripts from 2005-2009 in Thailand Major Sutchana Tabprasit Armed Forces Research Institute of Medical Sciences (AFRIMS), Royal Thai Army (RTA), Bangkok, Thailand

  2. Primary HIV-1 Infection • Acute infection • Rapid viral replication • 80-90% develop an acute syndrome characterized by flu-like symptoms • Broad HIV-1 specific immune response

  3. Recent HIV-1 Infection (Incidence) • Difference of HIV-1 antibody in various aspects • - Titer • - Proportion • - Isotype (avidity)

  4. Adults and children estimated to be livingwith HIV, 2008 UNAIDS. 2009 Report on the global AIDS epidemic

  5. Estimated number of adults and children newly infected with HIV, 2008 UNAIDS. 2009 Report on the global AIDS epidemic

  6. Methods for Detection Early HIV Infection (1) • Pre-seroconversion • HIV-1 RNA / DNA • p24 Antigen

  7. Methods for Detection Early HIV Infection (2) • Post-seroconversion • Less sensitive EIAs • IgG-capture BED-EIA • Avidity assays • Anti-p24 IgG3 Antibodies

  8. Advantages of HIV-1 Incidence • To monitor the effectiveness of the national prevention and control programs • To determine active area of HIV transmission • To design the possibility to conduct HIV vaccine trail

  9. Objective -Toestimate the HIV-1 incidence among the Royal Thai Army (RTA) conscripts

  10. Thailand

  11. 60,000 Males/year Recruitment of young Thai males occurs in April each year

  12. 4 3.5 3 2.5 2 1.5 1 0.5 0 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 HIV-1 SEROPREVALENCE OF YOUNG MEN ENTERING THE ROYAL THAI ARMY 1991-2009 4.5 3.7 3.5 2.9 3.0 2.4 HIV-1 Seroprevalence 2.1 1.9 1.6 1.3 1.2 0.7 0.7 0.6 0.5 0.5 0.5 0.5 0.5 0.5 Year

  13. The dot density of seroprevalence among recruits in the Royal Thai Army (RTA), 2005-2009. Positive = 1,316 dots Prevalence= 1,316/268,504 (0.5%) 1 dot = 1 prevalent case

  14. HIV Seropositive Detection From 2005-2009 268,504 ELISA I R NR WB/ ELISA II and III Positive Indeterminate N 149 1,316 BED-EIA

  15. IgG- Capture HIV-EIA

  16. 96-well plate is coated with goat anti-human IgG Principles of IgG- Capture HIV-EIA

  17. Principles of IgG- Capture HIV-EIA IgGantibodies fromplasma/serum 1. add specimen 2. add Biotinylated HIV-1 BED peptide (gp41) 3. add Streptavidin–HRP Conjugate 4. add substrate

  18. Principles of IgG- Capture HIV-EIA Plate Spectrophotometer Read at wavelength 450 nm with reference wavelength 630-650 nm

  19. Assay Validation : Run Control OD-N = OD/ Median OD of Calibrator R2

  20. The Algorithm of IgG Capture HIV-EIA Confirmed HIV-seropositive specimens Test in single If ODn > 1.2 Long-term Seroconversion If ODn ≤ 1.2 Repeat test in triplicate (Confirmatory) If Median ODn > 0.8 Long-term Seroconversion If Median ODn ≤ 0.8 Recent Seroconversion

  21. Results 0.26 0.25 0.20 Percent per year 0.19 0.14 Year 2005 2006 2007 2008 2009 Figure 1: HIV incidences at time of entry into the RTA 2005-2009

  22. Table 1: HIV-1 incidence among the RTA Conscripts From 2005-2009 by demographic factors

  23. Summary • Increasing trend of HIV incidence in the recent years alerts the active program for HIV prevention and control programs in Thailand • HIV incidence was higher in recruited subjects with older age. (22-30 years) • IgG capture BED is a promising predictor to estimate HIV incidence in the future.

  24. Acknowledgement • Conscripts of the Royal Thai Army • Armed Forces Research Institute of Medical Sciences (AFRIMS) • Army Institute of Pathology, King Mongkut Medical Center • Bureau of Epidemiology, Department of Disease Control of Ministry of Public Health (MOPH) • Thailand MOPH - U.S. Centers for Disease Control and Prevention (CDC) Collaboration

  25. Thank you so much

  26. www.nrl.gov.au

  27. Early HIV Infection Adapted from Parekh BS, McDougal JS. Indian J Med Res 2005;121(4):510-518.

  28. Methods for Estimating HIV Incidence www.nrl.gov.au

  29. Level Time since infection 155 days Difference between BED-CEIA and HIV screening test

  30. BED Branch Peptide Antigen

  31. Prevalence Formula Number of HIV-1 infection Number of total in the survey P = 100

  32. Adjustment of Incidence Formula R -ɛP (R/2) + N(w/365) - ɛN - ɛP/2) W=155 days R=Total testing recent in the BED-CEIA N=Total testing HIV negative P=Total testing HIV positive ɛ=False recent rate in those with ling term (>2weeks) infection I = 100

  33. Plate PlanFor Sample

  34. Plate PlanFor Sample

  35. Acceptable Median OD Ranges of Controls and Calibrator Acceptable ODn Ranges of Controls and Calibrator

  36. Highly active antiretroviral therapy (HAART) • Combination chemotherapy for HIV infection consisting of reverse transcriptase inhibitors and a viral protease inhibitor. • Produce marked increase in peripheral blood CD4+ T cells and decreases in HIV plasma RNA copy number. • Reduce plasma virus titers to below detectable levels for more than 1 year and slow the progression of HIV disease.

  37. Specificity Adjustment (Hargrove et al)

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