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Surveillance of recently acquired HIV infections among newly diagnosed individuals in the UK

Surveillance of recently acquired HIV infections among newly diagnosed individuals in the UK . Dr Samuel Lattimore. S. Lattimore, G. Murphy, R. Smith, J. Tosswill, D. Pillay, O.N. Gill & V. Delpech On behalf of the HIV Incidence Advisory and Working Group . Aim of RITA.

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Surveillance of recently acquired HIV infections among newly diagnosed individuals in the UK

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  1. Surveillance of recently acquired HIV infections among newly diagnosed individuals in the UK Dr Samuel Lattimore S. Lattimore, G. Murphy, R. Smith, J. Tosswill, D. Pillay, O.N. Gill & V. Delpech On behalf of the HIV Incidence Advisory and Working Group

  2. Aim of RITA “Incorporate RITA as part of the routine public health monitoring of all newly diagnosed HIV infections in England and Wales” RITA

  3. The system in England • Study period, 16 months between Feb 2009 to May 2010 • Estimated 7950 newly diagnosed infections during this time frame, from ~200 laboratories • 4116 aliquots from diagnostic samples were submitted to the national reference laboratory • 2480 linked to national epidemiological database (as of 1st July 2010) • Representing 2099 individuals • Epidemiologically representative sample

  4. Performance AxSYM avidity - guanidine as chaotrope Low avidity index (AI) indicates recent infection (<80%) >90% returned within 5 working days Results cascaded to the clinic via diagnostic laboratory

  5. Reclassification of low avidity specimens • 2099 samples, 280 low AI • CD4 <200 within 90 days of dx • Excluded: 20 • AIDS diagnosis within 90 days dx • Excluded: 7 • HIV positive test result more than 180 days previously • Excluded: 40 • 24 seen in the annual census of individuals accessing HIV treatment and care • 6 never received treatment • 10 on ARV when sample drawn • 8 ARV reported after sample date 5 1 0 51 excluded 9 5 1 30

  6. New dx 7950 Samples not received: ? Aliquots received: 4116 Unlinked: 1636 Linked: 2480 Duplicate samples: 381 Individuals: 2099 MSM: 889 Heterosexuals: 951 IDU: 39 Uncategorised: 223 AI 22 AI 198 AI 167 AI 719 AI 863 AI 2 AI 37 AI 88 R 143 LS 743 R 1 LS 38 R 21 LS 198 R 63 LS 888

  7. Recent infections by prevention group, England Feb 2009 – May 2010as of end June 2010

  8. Similar proportion of recent infections across all age groups Recent infections among MSM England, Feb 2009 – May 2010as of end June 2010

  9. Female: Highest in youngest age group Antenatal testing Decreasing with age Peaking again in 50+ Male: Later peak Decreasing with age Differential service access Recent infections among heterosexualsEngland, Feb 2009 – May 2010as of end June 2010 Exact permutation t.test, P = 0.083

  10. Conclusions • Experience from England demonstrates national surveillance of recent infections is possible in industrialised countries • Application of Laboratory tests for recent information require surveillance information • Estimated costs of 5000 specimens, between 77,000 - £138,000 • Among MSM • 1 in 6 recently infected • Similar proportion of recent infections across age groups • Among heterosexuals • 1 in 16 recently infected • Recent infections highest among 15-24 for women, 25-34 for men • UK acquired • Collect HIV test interval data from clinics to estimate HIV incidence in clinic attendees.

  11. www.hpa.org.uk/HIV Key word STARHS or RITA

  12. Acknowledgements National surveillance team Brian Rice, Ruth Smith, Meaghan Kall, Celia Penman, Sonia Ribero, Ragani Raghu & Vicky Gilbart National HIV survey team Alison Brown, Zheng Yin, Tom Hartney, Cuong Chau National virus reference lab Gary Murphy, Deenan Pillay, John Parry, Jennifer Tosswill, Elaine McKinney, Grace Mensah, Caroline Motamed And a very special thank you to Ruth Smith!

  13. SPARE SLIDES

  14. HET: 63 RHI • Infected in the UK (29; aOR 2.7) • White ethnicity (21; aOR 1.6) • UK born (29; aOR 3.1) • Diagnosed in London (40; aOR 3.2) • Age 15-24 (14; aOR 2.2) • MSM: 143 RHI • Infected in the UK (84; aOR 1.4) • White ethnicity (113; aOR 2.0) • UK born (74; aOR 2.4) • No association with age at dx Factors independently associated with RHI after exclusion All Samples: 229 recent infections • Male (180; 2.1) • Infected in the UK (114; aOR 2.4) • White ethnicity (142; aOR 1.8) • Born in the UK (93; 2.8) • MSM (143; aOR 2.9)

  15. 22 55 54 12 14 8 26 15 Proportion of RHI by age group • MSM • No association between age and RHI • Similar proportion RHI across age groups • Hets • Highest 15-24, decreasing to 35-49 (p<0.001) • More than double the proportion of recent infections among 50+ cf 35-49

  16. Is there a difference by sex among heterosexuals? Women Men Exact permutation t.test, P = 0.083

  17. Ongoing work • Testing patterns in age • Ascertaining country of infection • Combine with UK resistance database to explore subtype issues, and transmitted drug resistance • False long-standing infections relies on quantity and quality of surveillance data, especially self-reported testing history • Use RITA as a basis for estimating HIV incidence • Require knowledge of testing bias, representativeness and population estimates, repeat test pattern • Are we testing the right specimens? • Should AIDS /low CD4 specimens be called misclassified or should they just be excluded • Are we wrongly increasing the false recent rate by wrongly including specimens?

  18. RITA platform • Investigate the maturity of the anti-HIV antibody response by assessing its avidity. • Avidity index based upon the rational that avidity increases progressively with time from infection, thus low avidity indicates primary infection • Avidity index applied to other infections including toxoplasmosis, rubella, CMV, HCV, HBV and human herpes virus • AI for HIV described by Barbara Suligoi et al 2002 • Based on an automated AxSYM HIV-1/2gO assay (Abbott)

  19. Sensitivity and Specificity

  20. Why determine recent HIV infections (RHI) • Monitoring current burden, or prevalence of HIV infection in populations is a blunt tool for understanding: • Trends in transmission • Impact of behaviour change • Impact of public health interventions • Identifying RHI allows us to track patterns in HIV transmission • Reveal groups at greatest risk of HIV infections and • Tailor of health promotion initiatives to meet their needs • Highlight programmes most effective at reducing transmission • May be used to strengthen partner notification programmes, & target discussions on risk behaviour to recent timeframe.

  21. CD4 count at diagnosis among laboratory determined recent and long-standing infections • CD4 count significantly higher in laboratory determined recent infections (p<0.001) • 10% RITA recent have CD4 count <200 Median 344 580 275 529 400 450 R: Recent LS: Long standing

  22. R S T I T A A R H S Detecting recent HIV infections erological ecent • CD4 count at diagnosis • AIDS diagnoses • Previous positive HIV test esting nfection lgorithms esting ecent lgorithm IV SOURCE: Murphy G, Parry JV. Assays for the detection of recent infections with human immunodeficiency virus type 1. Euro.Surveill. 2008;13(36):18966. eroconversion

  23. Factors driving new diagnoses Changes in population Size (MSM) Migration and travel Improved reporting New HIV Diagnoses Transmission (incidence) Testing

  24. Proportion recent by risk group

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