Evaluating the risk of transfusion and transplant-transmitted monkeypox infections.

The recent emergence of monkeypox virus (MPXV) in the UK and elsewhere is of urgent public health concern. Several aspects of MPXV epidemiology and pathogenesis, including its systemic spread and viraemia during acute infection, furthermore represent an important potential threat to the safety of blood transfusion and organ transplantation. Reported infections in the UK have been exponentially increasing over the last 2 months, with 1552 reported cases in the UK by 7th July 2022. This is likely to be considerable underestimate given current limitations in diagnostic capacity and clinical diagnoses hampered by its similar disease presentations to other causes of rash and genitourinary disease. While MPXV infections are currently most widespread in gay, bisexual or other men who have sex with men, wider spread of MPXV outside defined risk groups for infection may prevent identification of infection risk in donors. While typically mild disease outcomes have been reported in UK cases, case fatality rates ranging from 1% to over 10% are reported for different MPXV strains in its source area in sub-Saharan Africa. Recipients of blood components and organs transplant, especially those who are immunosuppressed, may reproduce the greater systemic spread and morbidity of those infected through percutaneous routes. There is a potential risk of MPXV transmission and severe disease outcomes in blood and transplant recipients. In addition to current risk assessments performed in the UK and exclusion of donors with recent MPXV exposure, determining viraemia frequencies in donors and directly evaluating transmission risk would be of considerable value in assessing whether MPXV nucleic acid screening should be implemented.