Prevalence of HIV-1 in Blood Donations Following Implementation of a Structured Blood Safety Policy in South Africa

Abstract

Context The South African National Blood Service collects more than 700 000 units of blood annually from a population in which 11.4% is infected with human immunodeficiency virus 1 (HIV-1). The prevalence of HIV-1 in blood donations increased to 0.26% (1:385) in 1998, indicating that a significant number of window-period infective units were entering the blood supply (risk 3.4/100 000). Objectives To determine whether the implementation of a new donor selection policy and educational program introduced in 1999 was associated with reductions in the incidence and prevalence of HIV-1 in blood donations and the reduced transmission risk. Design We compared the prevalence of HIV-1 in 880 534 blood donations collected from 1999 through 2000 with the 791 639 blood donations collected from 2001 through 2002. We estimated the incidence of HIV-1 in 93 378 (1999-2000) and 67 231 (2001-2002) first-time donations and the residual risk for all donations in 2001-2002 using the less-sensitive enzyme-linked immunoassay and incidence-window period model. Setting All blood donors in the Inland region of the South African National Blood Service were analyzed. Intervention Donor clinics in high HIV prevalence areas were closed. Programs targeting repeat donors and youth were initiated and HIV risk behavior education programs were developed. Structured donor interviews and an enhanced donor self-exclusion questionnaire were institutionalized. Results The prevalence of HIV-1 in blood donations declined from 0.17% in 1999-2000 to 0.08% in 2001-2002 after the implementation of the new donor selection and education policy. The number of high-risk donations collected decreased from 2.6% to 1.7% (P<.001), and the likelihood of these donations being infected decreased from 4.8% to 3.25%. The likelihood of first-time donors being recently infected with HIV-1 decreased from 18% to 14% (P = .07) and respective incidence of high-risk donations collected decreased from 2.6% to 1.7%. Donations from the majority black population declined from 6.6% to 4.2% (P<.001). Analysis of HIV-1 incidence in 2001-2002 suggests a residual risk of collecting a window period infectious unit of 2.6/100 000. Conclusion The implementation of enhanced education and selection policies in South Africa was associated with decreased prevalence of HIV-1 in blood donations.