title: Human immunodeficiency virus prevalence, incidence, and residual transmission risk in first-time and repeat blood donations in Zimbabwe: implications on blood safety.
abstract: BACKGROUND
  National Blood Service Zimbabwe human immunodeficiency virus (HIV) risk management strategy includes screening and discarding of first-time donations, which are collected in blood packs without an anticoagulant (dry pack). To evaluate the impact of discarding first-time donations on blood safety the HIV prevalence, incidence, and residual risk in first-time and repeat donations (wet packs) were compared.
  
  
  METHODS
  Donor data from 2002 to 2010 were retrieved from a centralized national electronic donor database and retrospectively analyzed. Chi-square test was used to compare HIV prevalence with relative risk (RR), and the RR point estimates and 95% confidence interval (CI) are reported. Trend analysis was done using Cochran-Armitage trend test. HIV residual risk estimates were determined using published residual risk estimation models.
  
  
  RESULTS
  Over the 9 years the overall HIV prevalence estimates are 1.29% (n = 116,058) and 0.42% (n = 434,695) for first-time and repeat donations, respectively. The overall RR was 3.1 (95% CI, 2.9-3.3; p < 0.0001). The overall mean residual transmission risk of HIV window phase donations in first-time was 1:7384 (range, 1:11,308-1:5356) and in repeat donors it was 1:5496 (range, 1:9943-1:3347).
  
  
  CONCLUSIONS
  The significantly high HIV prevalence estimates recorded in first-time over repeat donations is indicative of the effectiveness of the HIV risk management strategy. However, comparable residual transmission risk estimates in first-time and repeat donors point to the need to further review the risk management strategies. Given the potential wastage of valuable resources, future studies should focus on the cost-effectiveness and utility of screening and discarding first-time donations.
authors.affiliation: Unit of PharmacoEpidemiology & PharmacoEconomics (PE2), Department of Pharmacy, University of Groningen, Groningen, Netherlands; Planning, Information & Research Department, Coordination Department, Medical Services Department, National Blood Service Zimbabwe; Department of Community Medicine, College of Health Sciences, University of Zimbabwe, Harare, Zimbabwe; Department of Clinical Pharmacy and Toxicology, Martini Hospital, Groningen, Netherlands.
authors.forename: Tonderai
authors.initials: T
authors.lastname: Mapako
authors.forename: David A
authors.initials: DA
authors.lastname: Mvere
authors.forename: McLeod E
authors.initials: ME
authors.lastname: Chitiyo
authors.forename: Simbarashe
authors.initials: S
authors.lastname: Rusakaniko
authors.forename: Maarten J
authors.initials: MJ
authors.lastname: Postma
authors.forename: Marinus
authors.initials: M
authors.lastname: van Hulst
mesh_terms: D001782:Blood Donors / Q000706:statistics & numerical data*; D058731:Blood Safety / Q000379:methods / Q000706:statistics & numerical data; D001803:Blood Transfusion / Q000706:statistics & numerical data; D015658:HIV Infections / Q000097:blood / Q000453:epidemiology* / Q000635:transmission*; D015528:HIV Seroprevalence; D015497:HIV-1 / Q000276:immunology / Q000302:isolation & purification; D006801:Humans; D015994:Incidence; D008403:Mass Screening / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D012698:Serologic Tests; D065227:Transfusion Reaction; D015030:Zimbabwe / Q000453:epidemiology