IMPROVING AND OPTIMIZING EARLY INFANT DIAGNOSIS

1. IMPROVING AND OPTIMIZING EARLY INFANT DIAGNOSIS Fausta Mosha: MD, PHD Laboratory Technical Officer – HIV/TB/Hepatitis WHO/AFRO a IAS 2019 21-24 July 2019

2. Presentation Outline • Indeterminate range • Confirmatory test • SOP for discordant results • EID algorithm

3. Definition Of Terms For Diagnostic Results • Positive Predictive value (PPV): the probability that an infant with a positive EID test result is HIV infected • Indeterminate range: A range of viral copy equivalents that would be too low to accurately diagnose as positive • Indeterminate results have a detectable target, as determined by the instrument, but the amplified viral signal is of such a low level that it could potentially be a false-positive result • False-positive result: HIV-uninfected infants incorrectly identified as HIV-infected • False-negative result: HIV-infected infants incorrectly identified as HIV-uninfected • Non-negative result: Any positive or indeterminate result • Discordant result: positive/detectable first test; negative second test • Cycle threshold ( Ct) : the point at which virus amplification is first observed during the course of repeated PCR cycles • The cycle threshold is inversely correlated to the amount of virus in the sample

4. Rationale For This Technical Update • Reduced MTCT rates – scale up of treat all policy in pregnant and breastfeeding women • Reduced viremia in infants • Decrease in positive predictive value of nucleic acid testing (NAT) • Lower specificity and higher proportion of false-positive test results • Implementation of Enhanced Postnatal prophylaxis (ePNP) • Delays in antibody development affects RDT use and interpretation

5. Indeterminate Range

6. MTCT rate across countries, 2017 • 60% reduction in new pediatric HIV infections in 21 high-burden countries in sub-Saharan Africa • New pediatric infections continue to occur and transmission dynamics have now shifted towards a proportional increase in transmission during the postnatal period Source UNAIDS Estimates

7. Positive predictive value decreases with reduced prevalence Feucht SAMJ 2012

8. As the MTCT rate decreases, so does the confidence in a positive result (positive predictive value) 20% MTCT 5% MTCT True positive False positive 10% MTCT 1% MTCT

9. Amount of viremia at diagnosisdecreasing in Option B+ era Haeri Mazanderani JAIDS 2018

10. Several technologies are available for EID testing Qualitative technologies generally report ‘detected’ or ‘not detected’, which gets understood as ‘positive’ or ‘negative’, respectively. All tests with WHO-PQ have high specificity > 98%

11. Amplification Curve Internal Control Sample 19th cycle Maritz JCV 2017

12. Ct Inversely Proportional To Viral Load Ct = 21 Maritz JCV 2017

13. Ct Inversely Proportional To Viral Load Ct = 24 Maritz JCV 2017

14. Ct Inversely Proportional To Viral Load Ct = 27 Maritz JCV 2017

15. Ct Inversely Proportional To Viral Load Ct = 30 Maritz JCV 2017

16. Ct Inversely Proportional To Viral Load Ct = 33 Maritz JCV 2017

17. Ct = 19 Ct = 33 Ct = 35

18. Without any indeterminate range… Based on a meta-analysis of data from Botswana, Namibia, Uganda, South Africa

19. However, not all are HIV-positive Based on a meta-analysis of data from Botswana, Namibia, Uganda, South Africa

20. However, not all are HIV-positive Based on a meta-analysis of data from Botswana, Namibia, Uganda, South Africa

21. However, not all ‘detectable’ results are truly HIV-positive infants Based on a meta-analysis of data from Botswana, Namibia, Uganda, South Africa

22. New WHO Recommendation Qualitative technologies generally report ‘detected’ or ‘not detected’, which is interpreted as ‘positive’ or ‘negative’, respectively. THEREFORE Identifying and repeat testing samples with low level viremia by introducing an indeterminate range can minimize unnecessary treatment initiation.

23. SOP for managing indeterminate test results • All indeterminate tests should be repeat tested on the same specimen, if and when available • If the same specimen cannot be repeat tested, then a new specimen should be requested and tested as quickly as possible • For specimens with two indeterminate test results, a new specimen should be requested • For infants repeatedly testing indeterminate, it is suggested that a team of experts review clinical and test information to determine the best follow-up care

24. How do we implement an indeterminate range? • Immediate options • If using Roche, implement a lab-based indeterminate range of Ct > 33 • Non-Roche assays, suppliers should provide an estimate of the Roche Ct > 33 equivalent • Preferred, long-term option: suppliers incorporate indeterminate range into their test and/or software. This is currently being discussed • For both options: • Training of health care workers to understand next actions and communication of indeterminate results • Training of laboratory staff to regularly assess and review cycle threshold values of all positive results • Store positive samples and repeat indeterminate test results immediately

25. Confirmatory test

26. Confirmatory test • Because of lowering MTCT and PPV rates, confirmatory testing is of utmost importance • To confirm all positive cases and maintain treatment/retention • To prevent false positives infants from lifelong treatment • Immediately start ART with a positive test result, and collect a new sample for confirmatory testing • Confirmatory testing can be done using conventional laboratory testing or point-of-care, if available

27. Managing Discordant Results

28. Managing discordant results and treatment Interruption • The 2016 WHO Guidelines recommended that in case of a confirmatory negative NAT, a third NAT should be performed before considering ART interruption. • In case the 3rd NAT is negative some factors should be considered when assessing patient for ART interruption: • The child should have signs/symptoms suggestive of HIV infection • Follow-up plan should be agreed upon with caregiver(s) and HCW • The introduction of an indeterminate range should potentially reduce the number of discordant test results

29. Factors to consider for follow up of infant undergoing treatment interruption • Active follow-up to ensure that a potentially infected infant is retained and re-initiated on treatment if virological rebound occurs • Virological rebound is expected to happen within 8 months of interruption in >99% of HIV-infected infants1 • Infants who develop signs and symptoms indicative of HIV infection should undergo immediate NAT testing • Breastfeeding and continued risk of transmission require follow-up and appropriate testing throughout the period of risk until final diagnosis 1 AvyViolari et al . Time to viral rebound after stopping ART in children treated from infancy in CHER. Abstract #137, CROI; March 4-7, 2018

30. SOP for discordant result: cessation of BF AFTER COMPLETION of the follow up post ART interruption • This option provides follow-up care to the infant for a minimum of 8 months after interruption of ART • Where possible, both EID and viral load tests should be performed at 4 weeks, 4 months, and 8 months after ART interruption

31. SOP for discordant result: cessation of BF BEFORE COMPLETION of the follow up post ART interruption

32. EID ALGORITHM

33. WHO 2016: EID Algorithm Is this still adequate in the option B+ era? NAT +: Start ART and request 2nd sample RDT at 9 mo If RDT pos: perform NAT Final diagnosis at 18 mo or 3 mo after cessation BF

34. Infant diagnosis is a process!Not just the 6-week test • Move to a multi-NAT algorithm: • Birth Testing (where of value) • 4 - 6 weeks NAT • 9 months (NATnot RDT) • Any time HIV exposed infants present sick • At nutrition and inpatient wards after determining exposure through maternal testing • Ensure confirmatory testing of all positive results • Complete diagnosis after exposure period ends

35. Infant diagnosis is a process!DO NOT FORGET THE FINAL DIAGNOSIS • Complete diagnosis after exposure period ends: • If with RDT: 3 months after cessation of breastfeeding • If with NAT: 6 weeks after cessation of breastfeeding • If BF extends beyond 18 months, the final diagnosis of HIV status can only be assessed at the end of breastfeeding

36. Moving forward… • The WHO 2018 updated recommendation enables access to more potent regimens and promote actions to ensure more accurate infant diagnosis. • Tools and guidance have already been developed to support country adoption and adaptation of these guidelines • Dedicated efforts are being planned to actively assist priority countries in their efforts to implement these recommendations • WHO continues to work with global partners to promote a collaborative and coordinated agenda that ensures innovation and acceleration for an AIDS FREE generation

37. Acknowledgment • Organizing team • WHO AFRO • CDs • HTH • WHO HQ

38. Thank you