Assessment of HIV transfusion transmission risk in South Africa: �A 10-year analysis following implementation of individual donation nucleic acid amplification technology testing and donor demographics eligibility changes

Marion Vermeulen , Nico Lelie, Charl Coleman, Wendy Sykes, Genevieve Jacobs,Ronel Swanevelder, Michael Busch, Gert van Zyl, Eduard Grebe, Alex Welte, and Ravi Reddy

Transfusion, Volume 59, January 2019;267-276

INTRODUCTION

• In 1998 despite screening with HIV p24Ag test, it was estimated that a significant rate (34 per million) infectious window period (WP) donations could be entering the blood supply, a projection supported by confirmed reports of transfusion-transmitted (TT) HIV infections each year^2,3
• Consequently, it was decided, after estimating that individual donation nucleic acid testing (ID-NAT) would reduce the TT HIV risk to 17 per million RBC transfusion⁴, to implement ID-NAT and CHANGE the risk management program (eliminating RACE-ETHNICITY based collection and utilization policies
• 1999: These measures were successful at reducing the estimated residual risk of TT HIV infection from 34 per million to 26 per million red blood cell (RBC) transfusion³ by using selective methods including which deemed UNETHICAL: Donor race-ethnicity

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Implemented :Individual –Donation Nucleic Acid Testing (ID-NAT)

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2. Heyns Adu P. Risk of transmitting HIV and other diseases with blood transfusion in South Africa. CME (South Africa Med Assoc) 1999;17:854-61

3. Heyns Adu p, Benjamin RJ, Swanevelder JP, et al. Prevalence of HIV-1 in blood donations following implementation of a structured blood safety policy in South Africa. JAMA2006;295:519-26

4. Fang CT, Field SP, Busch MP, et al. Human immunodeficiency virus-1 and hepatits C virus RNA among South Africa blood donor: estimation of residual transfusion risk and yield of nucleic acid testing. Vox Sang 2003;85:9-19.

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INTRODUCTION…continued

• 2016: Approximately 7.06 million are human immunodeficiency virus (HIV) positive, providing an estimated adult HIV prevalence and incidence of 18% and 0.91 per 100 person-years, respectively¹
• It was anticipated that implementation of ID-NAT would provide a safety buffer as donor eligibility policies were progressively modified to increase donations by the black African majority population⁴
• South Africa has the biggest HIV epidemic in the world, with 7.1 million people living with HIV. HIV prevalence is high among the general population at 18.9%_{(UNAIDS Data 2018)}

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1. Statistics South Africa. Mid year population estimates. Statistical release 2017 [cited 2018 Jul].

4. Fang CT, Field SP, Busch MP, et al. Human immunodeficiency virus-1 and hepatits C virus RNA among South Africa blood donor: estimation of residual transfusion risk and yield of nucleic acid testing. Vox Sang 2003;85:9-19.

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INTRODUCTION…continued

• South Africa: 1^st country globally to implement ID-NAT nationwide in 2005
• Steps taken in 3 October 2005:

1) ALL blood donations were screened for HIV RNA, Hep B DNA and Hep C RNA

2) p24Ag (HIV) testing was discontinued

3) Donor Race-Ethnicity was REMOVED (as marker of risk categorization)

4) Donor education and motivation campaign launched to increase the black African donor base

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STUDY DESIGN , MATERIALS & METHOD�

• Multiple regression analysis was performed to investigate the determinants of HIV-positive and nucleic acid testing yield donations
• Duration/Time: 2005-2015 (10 years)
• Number of donations, HIV prevalence, ID-NAT yield rate and residual TT HIV risk were analyzed by donor type, race-ethnicity, age, and sex.
• South African National Blood Service (SANBS) screen all blood using:
• 1. Chemiluminescent immunoassays (CLIA) by Prism, Abbott: Anti-HIV, HBsAg, Anti-HCV
• 2. ID-NAT by Procleix Ultro Plus, Grifols : HIV RNA, HepC RNA, HepB DNA

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STUDY DESIGN , MATERIALS & METHOD... continued�

• An extensive confirmation algorithm(previously described)⁵ is in place for HIV, which classifies donation based on blood collected at the time of donations into 4 categories:
• 1. HIV Negative
• 2. HIV Concordant Positive (Anti HIV POS, HIV RNA NAT POS)
• 3. HIV “ NAT yield”(Anti HIV Neg,RNA POS [NAT repeat reactive])
• 4. HIV “serology yield” (Anti HIV repeat POS, Western Blot POS, RNA Neg)

5. Vermeulen M, Lelie N, Sykes W, et al. Impact of individual -donation nucleic acid testing on risk of human immunodificicency virus, hepatitis B virus, and hepatitis C virus transmission by blood transfusion in South Africa. Transfusion 2009;49:1115-25

STUDY DESIGN , MATERIALS & METHOD

• Multiple regression analysis
• Duration/Time: 2005-2015 (10 years)

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A) Screening & Confirmation testing algorithm

• Prospective donor complete a donor questionnaire:
• 1. Examine donor health (to protect the donor)
• 2. Risk behavior (to protect the patient) e.g.:

“Are you HIV positive”; “In the past 6 months, have you had sexual contact with more than one person? ; “In the past 6 months, have you had sexual contact with a new sexual partner?'

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thus prohibit blood donation at this time & eliciting temporary deferral from blood donation until the risk behaviour has ceased

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STUDY DESIGN , MATERIALS & METHOD... continued

Blood Screening test:

• 1. Chemiluminescent immunoassays (CLIA) by Prism, Abbott: Anti-HIV, HBsAg, Anti-HCV
• 2. ID-NAT by Procleix Ultro Plus, Grifols : HIV RNA, HepC RNA, HepB DNA

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4 categories:

• 1. HIV Negative
• 2. HIV Concordant Positive (Anti HIV POS, HIV RNA NAT POS)
• 3. HIV “ NAT yield”(Anti HIV Neg,RNA POS [NAT repeat reactive])
• 4. HIV “serology yield” (Anti HIV repeat POS, Western Blot POS, RNA Neg)

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For NAT/Sero Yield cases: SANBS recalls these donor (approximately 70% return)

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• NAT yield: donor seroconverts at follow-up.

• Serology yield: donor must remain Western blot positive, BUT RNA Negative ( these reflect cases of spontaneous [elite] control or undisclosed antiretroviral theraphy

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HIV NAT Yield

• - For those return for follow up, samples from stored fresh frozen plasma (FFP) are tested with

i) Replicate Procleix Ultrio Plus (Grifols)

ii) Discriminatory HIV NAT (Grifols)

iii) Quantitative Polymerase chain reaction (qPCR) (Cobas Ampliprep/Cobas Taqman HIV-1 vs 2(Roche))

OR

Real time HIV-1 m2000rt (Abbott)

- samples also tested using a p24Ag assay (Innotest MAb, Immunogenetics) to ascertain whether have been detcted as HIV infected using the strategy in place before October 2005

- The South African National Institute of Communicable Diseases: sequences the Pol region of HIV to determine drug resistance and genotypes

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STUDY DESIGN , MATERIALS & METHOD... continued�

B) Characterization of donor demographics

- By self-reported predonation questionnaire(Sex, race-ethnicity, DOB, donation site)

- First time (FT) donor, repeat donor (< 1yr from previous donation),or lapsed (> 1yr from previous donation)

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C) HIV Infection detection rates

- Calculation for FT, repeat and lapsed donor

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HIV confirmed-positive donations* (x) x 100 = HIV prevalence (z) %

Total no. of blood donation from donor (y)

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*Concordant positive, confirmed NAT yield & confirmed sero yield

STUDY DESIGN , MATERIALS & METHOD... continued

D) TT risk analysis

- used the WP NAT yield ratio model⁶

- Detection periods:

i) 10.1days for NAT-positive/p24Ag-negative/anti-HIV negative detection period^7,8

ii) 5.3 days for p24Ag-positive/anti-HIV-negative detection period⁷

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6. Busch MP, Glynn SA, Stramer SL, et al. A new strategy for estimating risks of transfusion-transmitted viral infections based on rates of detection of recently infected donors. Transfusion 2005;45:254-64

7. Fiebig EW, Wright DJ, Rawal BD, et al. Dynamics of HIV viremia and antibody seroconversion in plasma donor: implications for diagnosis and staging of primary HIV infections. AIDS2003;17:1871-9

8. Vermeulen M, Coleman C, Mitchel J, et al. Comparison of human immunodificiency virus assays in window phase and elite controller samples: viral load distribution and implications of transmission risk. Transfusion 2013;53:2384-98

STUDY DESIGN , MATERIALS & METHOD... continued�

E) Lookback and traceback

- incosistent documentation, data only form 2010-2015

Donor triggered: a subsequent donation from the donor was confirmed HIV

Recipient triggered: a recipient alleged potential acquisition of HIV from a transfusion

If both recipient & donor HIV positive, phylogenetic sequencing was performed to confirm transmission (National Institute of Communicable Diseases)

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F) Regression analysis

- applied the Firth correction to NAT yield models¹¹

-Predictors : donor type, donor race-ethnicity, donor age, sex, geographic region of collection.

- Estimation was performed using the logistf R package¹²

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11. Firth D. Bias reduction of maximum-likelihood-estimates.Bio-metrika 1993;80:27-8

12. Heinze G, Ploner M.Logistf: Firth's bias-reduced logistic regression. R Package version 1.22;2016.

RESULT

A) Donor demographics

Black African donor : increasing from 6% in 2005 to 30% in 2015 (p < 0.00001)

FT Black African donor: increasing from 19% in 2005 to 54% in 25

Repeat Black donor: increasing 5% (2005) to 26% (2015) (p < 0.00001)

B) HIV Infection rates by donation and donor demographics categories

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-15,702 out of 7,736,125 (0.02%) were HIV-positive donations for over 10 years

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69% from FT donor

15% form lapsed donor

16% from frequent repeat donor

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- Significant increase 0.70% to 1.2% (p < 0.00001) for FT (all) in the early 5 years but decreasing to 1.14% (2015).

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- Prevalence of HIV in black African FT donor decreased from 3.18% to 1.97% (p < 0.00001)

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- In bivariate model,very large crude odds ratios (ORs) were observed for FT donation status (OR, 27.10; 95% CI, 25.95-28.31) black African race-ethnicity (OR, 57.26; 95% CI, 53.43-61.45), while female sex (OR, 2.36; 95% CI, 2.29-2.44)also highly significant

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-In multi-variate model, including controlling age and geographic region resulted in lower adjusted ORs but FT donation status (adjusted OR, 12.49; 11.93-13.07) black African race-ethnicity (adjusted OR, 30.20; 95% CI, 28.13-32.47), and female sex (adjusted OR,1.54; 95% CI, 1.49-.59) remained highly significant

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RESULT... continued

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Bivariate

Multivariate

RESULT... continued

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C) HIV NAT yield rates by donation and donor demographics categories

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- ID-NAT interdicted 481 (1:16,100) HIV-confirmed-positive donations that were

anti-HIV negative

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137 in FT donors

44 in lapsed donors

300 in frequent repeat donors

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- 462 confirmed HIV NAT yield donations were tested with p24Ag,

a) 285 tested p24g negative NAT yield donations

(183 repeat donor, 80 FT donor & 22 lapsed donor)

b) 177 tested p24Ag positive NAT yield donations

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- Black African race-ethnicity remained a substantial and significant predictor (adjusted OR, 32.63; 95% CI, 23.36-46.99), while colored-race ethnicity (adjusted OR, 6.44; 95% CI, 3.66-11.05) and female sex (adjusted OR, 2.19; 95% CI, 1.82,2.65) also remained significant

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RESULT... continued

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D) HIV serology yield rates by donation and donor demographics categories

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- 206 confirmed HIV antibody positive, NAT negative donations (2.6 per 100,00)

--> majority (186) from FT donor

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- There is a significant increase in serology yield donations from FT donors during the 10-year period from 3 per 100,000 (0.003%) to 39 per 100,000 (0.039%) (p= 0.0001)

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RESULT... continued

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E) Impact of screening startegy and changing donor demographics on WP transmission risk

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-WP NAT yield ratio model estimated overall residual risk of 11.9 per million RBC transfusion for the 10-year period

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-TT risk in 2005 would have been 24 per million RBC transfusion if ID-NAT not been implemented

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-WP TT risk was estimated to be much lower at 13.4 per million RBC transfusion in Year 10 following implementation of ID-NAT

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- FT donor have a 3-fold higher TT risk than repeat and lapsed donor

RESULT... continued

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F) HIV genotypes and drug resistance profiles in NAT yield donors

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- 481 NAT yield cases,

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168 were unable to be tested due to viral loads of < 1000 copies/mL*

86 could not be amplified (due to low viral load or RNA stability

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- 227 donations were genotyped:

204 (90%) : subtype C without any drug resistance

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18 (8%) : subtype C with 1 or more drug resistance mutations

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5 (2%): non subtype C (1 A1, 3 B [2 donations (0.9%) subtype B had drug mutations], 1 CRF02_AG)

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---> 20 donors are HIV RNA only positive and have drug resistance mutations suggests recent acquisition of HIV with drug resistance mutations

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* Minimal viral load for genetic testing at the National Institute of Communicable Diseases

RESULT... continued

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G) Lookback and traceback investigations

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- 2887 lookback investigations (of 5.8 million HIV-negative transfusion) were initiated

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15 patient (0.5%) tested HIV positive following transfusion without documentation of their infection status prior to the implicated transfusion

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8 pt showed no genetic linkage between donor n recipient viruses

2 pt were unlikely transfusion related due to a very short time interval to HIV-positive result following transfusion ( < 6 days)

3 pt were unresolved but were unlikely to be TT cases (1 was already on ART(3 months) after the transfusion and could not be amplified, 2 never returned for testing)

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1 pt was a CONFIRMED HIV transmission of a WP RBC unit.

- 100% sequence ID of HIV RNA isolated from recepient and donor follow-up samples

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RESULT... continued�

• Black donors increase from 6% to 30% in 2015 (p<0.000001)
• TT risk reduced from 24 to 13 per million transfusions.
• ID-NAT interdicted 481 HIV confirmed HIV positive (Anti HIV negative) (1:16,100) seronegative window donation with only 1 TT case (0.13 per million) documented
• Significant predictors of HIV positivity is still RACE ETHNICITY and DONOR TYPE
• Ratio FT donor of 12.5% (95% CI, 11.9-13.1)
• Black race-ethnicity of 31.1 (95% CI,28.9-33.4)
• the serology yields among HIV-infected donors increased from 0.27% to 2.4%

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DISCUSSION

• Screening with ID-NAT allowed substantial increase in the number and proportion of donation from the majority black African (fivefold both in FT and repeat donor) without reducing the safety of blood supply in South Africa
• TT HIV risk estimated in this study reduced from 24 per million in 2005 (with p24Ag and antibody but without ID-NAT testing) to 13.4 per million RBC transfusion in 2015 (with ID-NAT testing)
• Black African race ethnicity, female sex and donor age less than 30 were associated with higher prevalence of HIV infections, consistent with HIV infection demographic associations in the larger population in South Africa¹ -->due to sex inequality (compounded by cultural, legal and political factors that impede a woman's inability to protect herself from HIV¹⁴
• HIV prevalence in black African FT donors was reduced by 1/3 during the year ---> Improved predonation education programs

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1. Statistics South Africa. Mid year population estimates. Statistical release 2017 [cited 2018 Jul].

14. WHO. Consolidated guideline on sexual and reproductive health and rights of women living with HIV ;2017[cited 2018 Jul].

DISCUSSION... continued�

• Lookback program is not highly effective at detecting TT HIV as could not determine 63% of the 3000 cases investigated (40% unresolved, 14% deceased & 9% HIV positive at the time of transfusion)
• HIV NAT yield cases:

- FT donors 3-fold higher than repeat donor (OR, 2.85; 95% CI, 2.33-3.48)

- Black African donors was 38-fold higher than in white donors

By race ethnicity--> same rate for both FT and repeat donor--> suggesting noncompliance to the risk behaviour questions in the donor questionnaire, irrespective of prior donation education and experiance.

Similarly no difference in HIV NAT yield rates between FT and repeat donors in Asia and in Europe¹³

13. Bruhn R, Lelie N, Custer B, et al. Prevalence of human immunodificiency virus RNA and antibody in first-time,lapsed, and reepat blood donations across five international regions and relative efficacy of alternative screening scenarios. Transfusion 2013;53:2399-412

CONCLUSION

• ID-NAT screening does not remove all of the risk of TT HIV
• Along with increase in donations from black African donors, the TT HIV increased annually over 8 years form 4 peer million to 19 per million RBC transfusions, but then decreased in the last 2 years to 13 per million (attributed to the national rollout of ART and resultant 2-fold decrease in HIV incidence from 1.86% to 0.91% during the past decade in the general population¹), which is reassuring for the future.
• Change in donor eligibility and recruitment policies linked to introduction of ID-NAT were extremely successful
• Increasing serology yield are currently investigated which part due to donations by donor who were aware of their HIV infections and taking ART (suppressed their viral load below the detection limit of even ID-NAT testing)¹⁸

1. Statistics South Africa. Mid year population estimates. Statistical release 2017 [cited 2018 Jul].

18. Vermeulen M, van den Berg K, Jacobs G, Custer B, Swanevelder R, Jentch U, Reddy R, Wiesner L, Maartens G, Murphy El. Discovery of “false HIV elite controllers” among South African blood donors ISBT.Abstract 3B-S07-04. Copenhagen, 2017

CONCLUSION... continued�

• ID-NAT enabled the South Africa National Blood Service (SANBS) to increase the number of donations from black donor fivefold (both FT and repeat donor) while enhancing the safety of the blood supply
• In 10-year period , TT HIV case approximately 20-fold lower as compared with the period before the introduction of ID-NAT, when 2 cases per annum were observed.
• The trend in modeled residual risk must be continuously monitored to ensure the safety of the South African blood supply

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