Frequency of viral monitoring to detect cytomegalovirus infection and prevent disease in solid organ transplant recipients: An international, multicenter cohort study.

Cytomegalovirus (CMV) disease in solid organ transplant recipients (SOTr) can be prevented by antiviral prophylaxis or pre-emptive therapy (PET). The optimal CMV monitoring frequency remains unclear, and it is debated whether CMV surveillance after prophylaxis (SAP) is needed. CMV IgG donor (D)+/recipient (R)- or R+ SOTr in Zürich, Lausanne, and Copenhagen (2008-2021) were followed up for 6 months after the stoppage of CMV prophylaxis or transplantation if no prophylaxis was given. Associations between monitoring intervals and CMV disease were analyzed by Cox regression. Numbers needed to test (NNTs) with monitoring intervals of ≤7 vs >7 days were calculated. Among 3411 SOTr, CMV monitoring interval of 8 to 14 or >14 days vs ≤7 days were associated with higher risk of CMV disease (adjusted hazard ratio, 4.74; 95% confidence interval [CI], 2.17-10.36; and adjusted hazard ratio, 3.98; 95% CI, 1.92-8.26, respectively). The increased risk of CMV disease associated with monitoring intervals >7 days was consistent across subgroups. For the first 3 months of PET/SAP, the NNT was 11 (95% CI, 8-19) for D+/R- vs 71 (95% CI, 35-218) for R+ SOTr and did not differ between PET and SAP. Our findings support weekly CMV monitoring during first 3 months for recipients at risk, regardless of CMV preventative strategy. Close monitoring is more efficient in D+/R- SOTr, reflected by lower NNTs.