The presence of blood viral RNA in patients presenting with possible Middle East respiratory syndrome coronavirus (MERS-CoV) may be a very reliable indicator of the severity of the infection’s clinical course, according to a new study published in Emerging Infectious Diseases.
“Our study aimed to evaluate the diagnostic utility of blood specimens for MERS-CoV infection by using large numbers of patients with a single viral origin and to determine the relationship between blood viral detection and clinical characteristics,” wrote the authors, led by So Yeon Kim, MD, of the National Medical Center in Seoul, South Korea.
CDC/Cynthia Goldsmith/Maureen Metcalfe/Azaibi Tamin
MERS-CoV particles as seen by negative stain electron microscopy. Virions contain characteristic club-like projections emanating from the viral membrane.
The investigators recruited 21 MERS-CoV patients within South Korea, all of whom had been previously diagnosed by the Korea Centers for Disease Control and Prevention via respiratory samples and were of “a single viral origin.” All subjects contributed ethylenediaminetetraacetic acid (EDTA)-treated whole blood and serum specimens, from which viral RNA was extracted (Emerg Infect Dis. 2016 Oct 15;22[10]. doi: 10.3201/eid2210.160218).
Viral RNA was detected in 6 of 21 whole blood samples and 6 of 21 serum samples at hospital admission. However, because two patients were viral positive in either specimen subtype of EDTA-treated whole blood or serum, the overall detection rate for the population was 7 of 21 (33%). Being positive for blood viral RNA at admission was found to be associated with a fever of higher than 37.5 °C (99.5 °F) on the date of sample collection (P = .007), being placed on mechanical ventilation at some point during the clinical course (P = .003), extracorporeal membrane oxygenation (P = .025), and death (P = .025).
However, “between the blood viral RNA-positive and -negative groups, we found no differences in age, duration from symptom onset to diagnosis of MERS-CoV infection, or an invasive procedure before the specimens were obtained,” the investigators noted.
The takeaway, the authors underscore, is that although early blood viral RNA presence may not be a useful diagnostic tool, it “might be a good prognostic indicator of severe outcome” due to its high association with worse clinical course.
The research was funded by the National Medical Center Research Institute.