Middle East respiratory syndrome coronavirus (MERS-CoV) viral shedding in the respiratory tract: an observational analysis with infection control implications

Background: Since the first description of Middle East respiratory syndrome coronavirus (MERS-CoV), it has not been known how long patients shed the virus in respiratory secretions. Thus, we analyzed the available data on time to negative MERS-CoV test in patients with confirmed MERS-CoV infection and asymptomatic positive contacts. Methods: Data from repeated laboratory testing of respiratory samples received at the Saudi Arabian virology reference laboratory in Jeddah, Kingdom of Saudi Arabia from September 1, 2012 to September 31, 2013 were recorded. A real-time RT-PCR test for MERS-CoV was used. Data were analyzed by origin of sample, sample type, and MERS-CoV PCR test results. Results: Twenty-six individuals (13 patients and 13 contacts) had repeated testing done until a negative test was obtained. Most samples from MERS-CoV cases were tracheal aspirate/sputum (p = 0.0006) and most samples from contacts were nose and throat swabs (p = 0.0002). Kaplan-Meier curve analysis showed that contacts cleared the virus at a much earlier time than patients. On day 12, 30% of contacts and 76% of cases were still positive for MERS-CoV by PCR. Conclusions: Contacts cleared MERS-CoV earlier than ill patients. This finding could be related to the types of sample as well as the types of patient studied. More ill patients with significant comorbidities shed the virus for a significantly longer time. The results of this study could have critical implications for infection control guidance and its application in healthcare facilities handling positive cases. (C) 2014 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.