Human immunodeficiency virus prevalence, incidence, and residual transmission risk in first-time and repeat blood donations in Zimbabwe: implications on blood safety
- The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under Grant Agreement 266194. The views expressed in the manuscript do not reflect the views nor do they imply endorsement of the suggestion by the funders.
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.
Study Design and 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.
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).
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.