Transfusion-transmitted cytomegalovirus infection in the era of universal leukoreduction and pathogen inactivation: a contemporary review.

INTRODUCTION

Transfusion-transmitted cytomegalovirus remains a clinically significant risk in immunocompromised individuals, neonates, and transplant recipients. Despite widespread universal leukoreduction and pathogen-reduction technologies, uncertainty persists regarding residual risk and the role of CMV-seronegative blood components. This review summarizes the epidemiology, diagnostics, and prevention of transfusion-transmitted CMV.

METHODS

A review of the international literature was conducted using PubMed, Scopus, and transfusion medicine databases. Studies on CMV seroprevalence, transfusion transmission, leukoreduction efficacy, CMV-seronegative donor screening, and pathogen-reduction technologies were analyzed.

RESULTS

Cytomegalovirus seroprevalence among blood donors varies widely, from 30% to 40% in high-income countries to 80% to 90% in low- and middle-income countries. Universal leukoreduction to achieve residual leukocyte counts below 5 ×106 per unit removes more than 99.9% of leukocytes, meeting US Food and Drug Administration and Association for the Advancement of Blood & Biotherapies standards. Pathogen-reduction systems, particularly amotosalen/ultraviolet A light and riboflavin/ultraviolet light, provide multilog viral inactivation and are recognized as effective CMV-mitigation strategies, although theoretical residual risk from window-period or reactivated donors persists.

DISCUSSION: Transfusion-transmitted CMV is an exceptional event in the era of universal leukoreduction. Pathogen-reduction technologies represent the next evolutionary step toward a CMV-safe blood supply. Continued surveillance and cost-effectiveness studies are essential, particularly in high-prevalence, resource-limited settings.