Middle East respiratory syndrome coronavirus (MERS-CoV) is associated with significant mortality. We examined the utility of plasma MERS-CoV PCR as a prognostic indicator and compared the efficacies of IFN-α2a and IFN-β1a when combined with ribavirin in reducing MERS-CoV-related mortality rates.

We retrospectively analysed 32 patients with confirmed MERS-CoV infection, admitted between April 2014 and June 2014, by positive respiratory sample RT–PCR. Plasma MERS-CoV RT–PCR was performed at the time of diagnosis for 19 patients.

The overall mortality rate was 69% (22/32). Ninety percent (9/10) of patients with positive plasma MERS-CoV PCR died compared with 44% (4/9) of those with negative plasma MERS-CoV PCR. Mortality rate in patients who received IFN-α2a was 85% (11/13) compared with 64% (7/11) in those who received IFN-β1a (P = 0.24). The mortality rate in patients with renal failure (14), including 8 on haemodialysis, was 100%. Age >50 years and diabetes mellitus were found to be significantly associated with mortality (OR = 26.1; 95% CI 3.58–190.76; P = 0.001 and OR = 15.74; 95% CI 2.46–100.67; P = 0.004, respectively). The median duration of viral shedding in patients who recovered was 11 days (range 6–38 days). Absence of fever was noted in 5/32 patients.

Plasma MERS-CoV RT–PCR may serve as an effective tool to predict MERS-CoV-associated mortality. Older age and comorbid conditions may have contributed to the lack of efficacy of IFN-α2a or IFN-β1a with ribavirin in treating MERS-CoV. Absence of fever should not exclude MERS-CoV.