Prognostic Value of PCR Cycle Threshold Value in Crimean-Congo Hemorrhagic Fever, Iraq, 2022-2023

Using laboratory and epidemiologic data collected in 2022 and 2023 in Iraq, we aimed to evaluate the diagnostic and prognostic performance of reverse transcription PCR (RT-PCR) in Crimean-Congo hemorrhagic fever (CCHF) patients and to identify factors associated with disease outcomes. CCHF was confirmed in 955 hospitalized patients. Among those, RT-PCR analysis showed that blood specimens from deceased patients had a lower median cycle threshold (Ct) value than did those who recovered; we used those data to determine a cutoff value. Univariate and multivariate logistic regression analysis indicated that low Ct values, hemorrhagic symptoms at admission, and age >15 years were independent determinants of fatal CCHF outcome. Viral load and patient age play key roles in the outcome of CCHF in Iraq. Ct value at admission, as a proxy for viral load, serves as a practical indicator to guide clinicians in managing CCHF patients.