SMARTube TM as a Test for Recent Infection

Transcription

1 SMARTube TM as a Test for Recent ReshmaKassanjee 1,2, Alex Welte 1,2, Tamar Jehuda-Cohen 3 1 University of the Witwatersrand, South Africa 2 South African DST/ NRF Centre forepidemiological Modelling and Analysis, South Africa 3 Smart Biotech Ltd, Israel

2 Tests for Recent (TRI s) What? Classify infections as recently or non-recently acquired Why? Incidence estimation Using cross-sectional surveys rather than prospective follow-up Challenges? Achieve certain performance characteristics (not specificity / sensitivity) Surveillance, not diagnostics 2

3 Performance Requirements Healthy Recent Non-recent 3

4 Performance Requirements Healthy Recent Non-recent 3

5 Performance Requirements Healthy Recent Non-recent False recent rate Low 3

6 Performance Requirements Healthy Recent Non-recent Mean recency duration High False recent rate Low 3

7 Performance Requirements Healthy Recent Non-recent Mean recency duration High ( > 3 months ) False recent rate Low ( < 5% ) Power in tests of incidence: 3

8 SMARTube TM Technology Stimulating Maximal Antibody Response Tube In-vitro stimulation of antibody producing B cells Allows for earlier detection of HIV infection Antibody Level Stimulated Unstimulated Time after 4

9 SMARTube TM Technology Stimulating Maximal Antibody Response Tube In-vitro stimulation of antibody producing B cells Allows for earlier detection of HIV infection Antibody Level Stimulated Unstimulated Time after Novel biomarker for a test for recent infection Stimulation Index: SI = Recent infection SI > SI Threshold Stimulated Antibody Level Unstimulated Antibody Level 4

10 Performance of a RecencyTest Using SMARTube TM Convenience sample of seropositiveindividuals in China, method of maximum likelihood 5

11 Performance of a RecencyTest Using SMARTube TM Convenience sample of seropositiveindividuals in China, method of maximum likelihood False Recent Rate Low SI Threshold High SI Threshold Mean Recency Duration 5

12 Performance of a RecencyTest Using SMARTube TM Convenience sample of seropositiveindividuals in China, method of maximum likelihood False Recent Rate Low SI Threshold Insufficient evidence that > 5% 1.1 High SI Threshold Mean Recency Duration 5

13 Performance of a RecencyTest Using SMARTube TM Convenience sample of seropositiveindividuals in China, method of maximum likelihood False Recent Rate Low SI Threshold Insufficient evidence that > 5% Insufficient evidence that < 155 days High SI Threshold Mean Recency Duration 5

14 Conclusion Preliminary analysis provides promising results Test for recent infection using SMARTube TM Low false recent rate AND High mean recency duration Recommend a larger dataset of better characterised specimens is analysed There is scope for non-traditional approachesfor constructing tests for recent infection 6

15 To find out more... Poster, and Questions 7

16 Surveillance NOT Diagnostics Why Specificity and Sensitivity are not of concern... Example: Estimating the incidence of Flu Healthy Flu Recovered Individuals remain infected for 3-7 days, average of 5 days Incidence Prevalence (5/365) Whether a particular person is still infected 4 days after infections is not of concern for incidence estimation