Reconsideration of blood donation testing strategy for human T‐cell lymphotropic virus in Australia

Abstract

Transfusion-transmission of HTLV is a minimal risk in Australia even without testing. However, any revision of testing strategy must consider not only risk and cost-effectiveness, but also stakeholder, ethical and regulatory perspectives. Considering all relevant criteria, new-donor testing is judged the optimal strategy because it is able to achieve almost the same outcomes as universal testing, at a fraction of the cost.

Estimation of human T‐lymphotropic virus incidence in blood donors from observed prevalence

“…The discrepancy between this and the observed ratio is consistent with repeat donors having a significantly lower incidence than new donors. This is expected as vertical transmission is the most significant risk factor for infection in most populations , and importantly, this has also been demonstrated in Australian blood donor surveillance data . Therefore, new‐donor testing detects this risk from childhood and repeat donor testing detects further adulthood risk from that time‐point.…”

“…During the period 2004 to 2014, the overall presence of HTLV infection was 29·83 per million new donations and 0·16 per million repeat donations , giving a prevalence to incidence ratio of 186:1. In a theoretical steady state population, this ratio should be close to the average duration of disease .…”

“…Under the Blood Service's risk tolerability framework, the risk of transmission of HTLV via transfusion is considered to be acceptable provided it remains lower than 1 in 1 million, and tolerable up to 1 in 500 000. Using the modelling and dataset previously described , 3·6 incident HTLV infections in repeat donors per year sustained over a period of 10 years would be associated with a transfusion‐transmission risk of 1 in 1·09 million cellular components. This is equal to an incidence of 3·2 infections per million repeat donations.…”

Human T‐cell lymphotropic virus: A simulation model to estimate residual risk with universal leucoreduction and testing strategies in Canada

“…Moving from a universal testing strategy to testing only first‐time donors would have a negligible impact on risk (1 potentially infectious unit per 7·1 million). Similar to England, Australia and France, this is because first‐time donors comprise the bulk of the risk .…”

“…Indeed, some European countries with universal prestorage leucoreduction have not seen the need to implement testing at all . More recently, the benefit of combining both universal testing and universal prestorage leucoreduction has been questioned, resulting in decisions to switch to testing only first‐time donors in England and Ireland . To assess the risk of changing the testing algorithm in Canada, we have developed a simulation model to estimate the risk of an infectious unit of red cell concentrate, random donor platelets or apheresis platelets being released into inventory with universal prestorage leucoreduction in place.…”