Abstract

Background: Pathogen reduction technologies treat platelet components to inactivate a broad range of viruses, bacteria and parasites and so reduce the residual risk of transfusion-transmitted infection, but the treatment may also affect the clinical efficacy and safety of the platelets. This study systematically reviewed the randomised controlled trials comparing pathogen-reduced platelets with standard platelets and performed a de novo random-effects metaanalysis of their clinical outcomes, together with a secondary synthesis of pathogen-inactivation efficacy against arboviruses. Methods: The review was registered and conducted in accordance with the PRISMA statement. A systematic search identified randomised controlled trials of pathogen-reduced versus standard platelets in patients requiring transfusion. Study-level data were extracted independently, the risk of bias was appraised with the Cochrane RoB 2 tool, and outcomes were pooled by the DerSimonian and Laird randomeffects model with the I-squared statistic. Thirteen trials (2868 patients) were included. Results: Pathogen-reduced platelets showed a non-significant trend toward more clinically significant bleeding (WHO grade 2 or above; risk ratio 1.14, 95% CI 0.99 to 1.31) and did not increase severe bleeding (risk ratio 1.21, 95% CI 0.80 to 1.83) or serious adverse events (risk ratio 1.03, 95% CI 0.87 to 1.20). They were associated with substantially higher platelet refractoriness (risk ratio 2.38, 95% CI 1.90 to 2.98) and alloimmunisation (risk ratio 1.77, 95% CI 1.47 to 2.13), lower corrected count increments (1-hour mean difference -7.03) and more platelet transfusions per patient (mean difference 1.09). Most trials were at low or some-concerns risk of bias. In the secondary synthesis, an adequate log reduction was achieved for 16 of 17 arboviruses by at least one platform, with riboflavin-based inactivation the least effective. Conclusion: Pathogen-reduced platelets do not increase severe bleeding or serious adverse events but carry a consistent cost in platelet potency, manifesting as increased refractoriness, alloimmunisation and transfusion requirement. Pathogen inactivation is adequate for most arboviruses but varies by platform. The evidence supports continued and expanded implementation where transfusion transmitted infection risk and resources justify the additional cost. 

Keywords: Pathogen reduction technology, Pathogen inactivation, Platelet transfusion, Transfusion-transmitted infection, Blood safety