Impact of Testing Strategies to Reduce Transmission Risk for HBV

1. Impact of Testing Strategies to Reduce Transmission Risk for HBV Ravi Reddy, M Vermeulen South African National Blood Service (SANBS) 29 July 2013

2. Overview of SANBS HQ in Johannesburg • SANBS is a private not for profit company operating on a fee for service basis • Provides a vein to vein blood transfusion service in 8 of the 9 provinces in SA. • WPBTS in Western Cape • 807,000 units of blood collected annually (100% voluntary) – 2 800 units bled daily • 2 testing centres - Johannesburg and Durban • Also test for Namibia BTS (ID-NAT as well) • 7 blood processing centres • 82 blood banks serving > 600 hospitals and clinics. • SANBS is accredited with the South African National Accreditation System (SANAS) • Specific laboratories are ISO 17025 accredited

3. Donation Testing Strategy • Quality assured testing of each donation • EQAS and internal QC systems in place • Serology is mandatory • Anti-HIV-1,2, anti-HCV, HBsAg • Quality assured testing with sensitive serology assays leads to detection of most of the viral positive donations cost effectively • Individual Donation Nucleic Acid Testing (ID-NAT) • Implemented in October 2005 • Primarily to reduce risk of HIV window period transmission but also HBV transmission as well

4. Rationale for ID-NAT in South Africa • HIV prevalence in blood donors 0.21% • HBV prevalence in Blood Donors is 0.1% • Implemented ID-NAT testing in October 2005 • ULTRIO® assay on the TIGRIS® platform for: • HIV-1 RNA • HCV RNA • HBV DNA • Serology testing for anti-HIV, anti-HCV and HBsAg done concurrently • Evaluated and implemented Ultrio Plus assay in May 2011 because of increased sensitivity for HBV detection in window period

5. Geographic Distribution of Chronic HBV Infection HBsAg Prevalence ³8% - High WHO 2-7% - Intermediate <2% - Low

6. HBV 5 Year data

7. Hepatitis B Summary • 476 NAT+, HBsAg negative donations detected in 5 years • Hundreds of cases of transmission via transfusion prevented • ID NAT testing has had a significant positive impact on reducing risk of HBV transmission via blood transfusion • However still a risk of non detection of very low viral load donations • One confirmed HBV transmission on a donation that tested negative with routine serology and ID-NAT • Donor triggered look back as subsequent donation positive • Ultrio Plus Assay evaluated and in 2010/11

8. Confirmed pre-ID-NAT WP transmission case • Donor triggered look back – RBC • Platelet concentrate – Patient unable to be traced • Donor details • 47 year old white male (low risk, regular donor) • 54 previous donations • Negative donation – 26/11/2008 • Date of Transfusion – 10/12/2008 • Positive donation – 26/01/2009

9. ID-NAT WP transmission case * 3.5 months after transfusion

10. Additional tests to Determine if Recipient infection caused by Transfusion • Donor plasma index donation (26/11/08) • SANBS 3 out of 30 replicates positive • Gen Probe 7 out of 30 replicates positive with Ultrio Plus • Phylogenetic analysis/sequencing • Donor and recipient – genotype A • Intra group nucleotide divergence • Donor/recipient 0.31% (99.7% Shared Identity) • Transmission by Blood Tranfusionconfirmed

11. Ultrio, Ultrio Plus, TaqScreen Study performed • Compare Sensitivity of NAT assays with a range of samples • 10 000 random samples • 40 HIV ID-NAT yield samples • 107 HBV ID NAT positive samples on Ultrio • HBsAg positive, HBV NAT negative samples • Other samples (HIV Window period transmission sample and HBV window period transmission sample)

12. Proportion reactive per NAT option on 107 Ultrio HBV ID-NAT yield samples % reactive tested in 6 replicates in each test option p< 0.00001 p< 0.00001 p< 0.00001 P= 0.00015 NAT option

13. Proportion HBV NAT reactive on WP* and OBI yield samples % reactive NAT option

14. Percent ID-NAT reactive on HBsAg+/Ultrio- yield samples % reactive (12 reps) copies/ml* *determined by probit analysis in Ultrio Plus against Eurohep standard

15. HBV ID-NAT Yields – One year Data Ultrio (2010 vs. Ultrio Plus 2011)

16. Viral load distribution in all HBV NAT yields detected by Ultrio versus Ultrio Plus HBV-DNA cps/mL

17. Estimated WP reduction with Ultrio and Ultrio Plus (14.5 vs 24.7 days; 1.7 fold) Start WP Ultrio Plus Ultrio HBsAg cps/ml HBsAg S/CO=1 3000 cps/ml Ultrio 50% LOD 63 cps/ml Ultrio Plus 50% LOD 4.1 cps/ml ID50 3.16 cps/ 20 ml 24.7 days 12.9 days days Ultrio Plus HBsAg eclipse WP 14.5 days 22.9 days WP Ultrio

18. Probable OBI transmission case ¥ 100 % homology of whole HBV genotype D genome sequence of donor sample 11/4/12 and recipient sample 4/7/12 (analysis kindly performed by Dr Marco Koppelman, Sanquin, Amsterdam) * Estimated from 5/20 reps Ultrio Plus reactive by probit analysis ( 5.1% probability of transmission estimated with ID50 of 316 virions)

19. Testing Strategy for Hepatitis B • Countries with high incidence/prevalence of HBV need to carefully review algorithms for HBV testing and assay selection • Maximise safety and minimise product discard • High prevalence countries • HBsAg and ID-NAT but not anti-HBc • No discard of anti-HBc positive units (6-8% of products usable) • Majority of early and occult infections detected • Minimal risk of not detecting post HBV DNA window period donations and some OBI’s • Ultrio Plus in ID-NAT format has significantly improved sensitivity and reduced risk

20. Course of HBV markers and residual transmission risk with ID-NAT OBI transmission risk unknown 1st WP ~10 days (Ultrio Plus) 2nd WP < 1day (Ultrio Plus) Vermeulen et al, Transfusion 2012;52:880-892.

21. SANBS Algorithm for HBV Testing • ID-NAT and HBsAg testing • Concordant positive – confirmed • ID-NAT only (2 x U+ and dHxV) • Non repeat reactive – donation discarded, anti-HBc and anti-HBs marker added • 0.12% of donations discarded (mostly false positive) • Donor not notified • When donor returns • Additional tests performed • Blood can be used if all routine tests and anti-HBc negative

22. Algorithm for HBV Testing (cont’d) • ID-NAT repeat reactive (2 out of 4), serology negative • Additional tests on plasma bag • Donor recalled and additional tests done • If confirmed positive defer donor • If deferral, medical division contacts and counsels donor • If all tests on follow up donation negative (review need for additional tests or re-instate)

23. HIV infections in six years of ID-NAT screening of 4,520,230 donations anti-HIV HIV-RNA 7993 (96.5%) HIV RNA +, anti-HIV + concordant HIV RNA –, anti-HIV + elite controller 64 (0.77%) HIV RNA +, anti-HIV– window period 228 (2.8%) • 59 in first time donors (0.71%) • 4 in lapsed donors (0.05%) • 1 in repeat donor (0.01%)* 82/228 (38.4%) HIV-Ag + 136 HIV-Ag-, RNA+ infections avoided (1:33,237)

24. Impact of ID NAT on Blood Safety - HIV • Significant positive impact on blood safety contributing to major public health success story • 136 ID- NAT positive, anti-HIV negative, p24 antigen negative donations detected in 6 years of testing. • Without ID-NAT there would have been numerous HIV transmissions via blood transfusion • Major public health success story • Increased collections by 95 000 units over 5 years and increased confidence in the blood supply • Could increase Black donors from 7% to 31% of donor base over 5 years • Since ID NAT implementation, no reported case of HIV transmission since October 2005 • HIV prevalence in blood donors has increased (0.07% to 0.23%) • Highlights impact of ID-NAT on improving blood safety

25. Summary • Implementation of ID-NAT testing has resulted in a significant increase in safety of the South African blood supply compared to previous testing strategy • ID-NAT continues to interdict infectious donations that are missed in mini pool format • SANBS evaluation and one year data confirmed that Ultrio Plus is more sensitive than Ultrio for HBV

26. Thank You