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

Abstract

BACKGROUND: In 1998 we estimated that 34/million infectious window period donations were entering the blood supply at the South African National Blood Service. Selective use of donations based on donor race-ethnicity reduced this risk to 26/million donations but was deemed unethical. Consequently, in 2005 South African National Blood Service eliminated race-ethnicitybased collection policies and implemented individual-donation nucleic acid testing (ID-NAT). We describe the change in donor base demographics, human immunodeficiency virus (HIV) detection rates, and transfusion-transmissible HIV risk. STUDY DESIGN AND METHODS:In ten years 7.7 million donations were tested for anti-HIV and HIV RNA. Number of donations, HIV prevalence, ID-NAT yield rate, serology yield rate and residual transfusion-transmissible HIV risk were analyzed by donor type, race-ethnicity, age, and sex. Multiple regression analysis was performed to investigate the determinants of HIV-positive and nucleic acid testing yield donations. RESULTS:The combined strategy of increasing donations from black donors and implementing ID-NAT increased the proportion of donations from black donors from 6% in 2005 to 30% in 2015 (p < 0.00001), and reduced the transfusion-transmissible risk from 24 to 13 per million transfusions. ID-NAT interdicted 481 (1:16,100) seronegative window period donations, while one transfusiontransmissible case (0.13 per million) was documented. Race-ethnicity and donor type were highly significant predictors of HIV positivity, with adjusted odds ratio for first-time donors of 12.5 (95% confidence interval, 11.9-13.1) and for black race-ethnicity of 31.1 (95% confidence interval, 28.9-33.4). The proportion of serology yields among HIV-infected donors increased from 0.27% to 2.4%. CONCLUSION: ID-NAT enabled the South African NationalBlood Service to increase the number of donations from black donors fivefold while enhancing the safety of the blood supply.A ccording to a "between-census" community survey done in 2016 that sampled 1.3 million households of the 56 million people living in South Africa, approximately 7.06 million people are human immunodeficiency virus (HIV) positive, providing an estimated adult HIV prevalence and incidence of 18% and 0.91 per 100 person-years, respectively. 1 In this environment, the South African National Blood Service (SANBS) collects approximately 800,000 blood donations annually from voluntary nonremunerated blood donors, which are processed into blood components that are provided to approximately 400,000 patients each year. ABBREVIATIONS: ART = antiretroviral therapy; FT = first-time; ID-NAT = individual donation nucleic acid testing; MID 50 = 50% minimum infectious dose; p24Ag = p24 antigen; SANBS = South African National Blood Service; TT = transfusion-transmitted; WP = window period.

Transfusion of HIV‐infected blood products despite highly sensitive nucleic acid testing

“…In some cases, the convergence of both situations dramatically reduced the NAT sensitivity, yielding false‐negative results . Only one recent case, described in South Africa, showed an ID‐NAT failure in detecting HIV RNA . In the case we describe here, the strain sequenced from the blood donor belongs to HIV‐1/M subtype B, the most prevalent subtype in France in the general population and in blood donors (67% of strains found in blood donors) .…”

“…Between 2000 and 2018, more than 20 HIV‐infected blood components that tested HIV antibody and NAT negative, were reported worldwide, with or without transmission to the recipients . These cases correspond to two particular situations: 1) the presence of polymorphism in HIV strain, leading to mismatches between primers/probes and the viral sequence, and 2) failure to detect HIV RNA when NAT is performed in minipools .…”

The evolving blood donor deferral policy for men who have sex with men: impact on the risk of HIV transmission by transfusion in France

“…We used a 9-day window period based on the high sensitivity of HIV NAT testing currently in use in our country, which is in accordance with recent reports. 23,[27][28][29][30] However, as our study consisted of evaluating a differential risk, the length of the window period did not impact our results.…”

Direct comparison of three residual risk models for hepatitis B virus window period infections using updated input parameters

“…In South Africa, we recently estimated the residual transfusion transmission risk by window period (WP) donations for human immunodeficiency virus type 1 (HIV‐1) infection over a 10‐year screening period in which both serologic testing and individual donation nucleic acid amplification technology (ID‐NAT) were used . In this period, 344 HIV WP NAT yields and 4491 anti‐HIV seroconversions were detected in 6 805 478 repeat plus lapsed donations.…”