(P-BB-59) Optimizing donor malaria management in Australia using a risk and cost effectiveness analysis

Background/Case Studies: Transfusion-transmitted (TT) malaria, although rare, remains a blood safety issue. Australia manages the risk through screening questions identifying anyone who spent time in endemic areas and by testing for total antibodies to Plasmodium species (Captia Malaria EIA, Trinity Biotech USA) ≥4 months after return. However, most of the risk is from donors born or who have lived in malarious countries (‘residents’), not short-term travellers (‘visitors’). Our study evaluated various malaria testing strategies to optimize Australian malarial risk management.

Study

Design/Methods: A residual risk model was developed considering the risk of visitors versus residents based on comparative rates of confirmed parasitaemia by PCR in those that tested antibody positive. A test failure rate was estimated, and the incidence of parasitaemia was adjusted based on literature values dependent on the testing time and malaria species. The testing strategies assessed included the status quo, no testing with differing time-based restrictions and selective testing of residents only (Table 1). A decision-analytic model was developed to evaluate the cost-effectiveness of five testing strategies from a health provider perspective. The impact of transfusion-transmitted malaria was quantified using disability adjusted life years (DALYs) and the costs associated with testing malaria and managing transfusion transmission were included.

Results/Findings: Results are shown in the Table 1. The estimated residual risk was 1 in 2.3-67.9 million. Whilst no testing and a four-month visitor restriction and 3-year resident restriction cost the least and had an acceptable risk, there was a 20,000 net yearly donation loss. Testing residents only after four months results in no change in the risk and DALYs lost but costs less.

Conclusions: The preliminary results demonstrate no testing with time-based restrictions is an acceptable strategy from a risk perspective, however the donation loss is significant. Testing residents only does not change the residual risk while being substantially less expensive and represents the best selective testing option.

Importance of research: Management of malaria blood safety risk varies by country, the optimal strategy is unclear. A risk model was developed and a cost-effectiveness analysis was performed to identify the optimal strategy in Australia. This found the current testing strategy of testing all who visit a malaria area is too conservative, and recommend moving to either no testing with time-based deferral if the donation loss is acceptable, or a selective testing strategy for donors at significant increased risk only