Viral RNA in Blood as Indicator of Severe Outcome in Middle East Respiratory Syndrome Coronavirus Infection

Abstract

We evaluated the diagnostic and clinical usefulness of blood specimens to detect Middle East respiratory syndrome coronavirus infection in 21 patients from the 2015 outbreak in South Korea. Viral RNA was detected in blood from 33% of patients at initial diagnosis, and the detection preceded a worse clinical course.

Keywords: MERS-CoV; Middle East respiratory syndrome; blood; coronavirus; prognosis; real-time PCR; viruses; zoonoses.

Figure

Differences in survival among Middle East respiratory syndrome coronavirus–infected patients, South Korea, 2015. A, B) Survival difference between the blood viral RNA-positive (solid line) and -negative (broken line) groups. Survival was defined as the time from initial confirmatory diagnosis to death before hospital discharge (A) (Kaplan-Meier survival analysis, log rank p = 0.009; Breslow p = 0.006) and as the time from symptom onset to death (B) (Kaplan-Meier survival analysis, log rank p = 0.017; Breslow p = 0.015). C, D) Survival difference between the high respiratory viral load (solid line) and low respiratory viral load (broken line) groups. Viral loads were classified into 2 groups: patients who harbored viral loads above the median load of patients and patients who harbored below. Survival was defined as time from initial confirmatory diagnosis to death. Cycle threshold (C_t) values were calculated for real-time reverse transcription PCRs targeting the upstream of envelope region (C) and open reading frame 1a region (D) (Kaplan-Meier survival analysis, log rank p = 0.739; Breslow p = 0.630). Tick marks along data lines indicate data-censored time points.