title: Middle East respiratory syndrome coronavirus (MERS-CoV) viral shedding in the respiratory tract: an observational analysis with infection control implications.
abstract: 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.
authors.affiliation: College of Medicine, Alfaisal University, Ministry of Health, Riyadh 11176, Kingdom of Saudi Arabia. Electronic address: zmemish@yahoo.com.
authors.forename: Ziad A
authors.initials: ZA
authors.lastname: Memish
authors.affiliation: Ministry of Health, Riyadh, Kingdom of Saudi Arabia.
authors.forename: Abdullah M
authors.initials: AM
authors.lastname: Assiri
authors.affiliation: Johns Hopkins Aramco Healthcare, Dhahran, Kingdom of Saudi Arabia; Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Jaffar A
authors.initials: JA
authors.lastname: Al-Tawfiq
mesh_terms: D018352:Coronavirus Infections / Q000517:prevention & control / Q000821:virology*; D006801:Humans; D017053:Infection Control; D065207:Middle East Respiratory Syndrome Coronavirus; D012137:Respiratory System / Q000821:virology*; D012529:Saudi Arabia; D017201:Virus Shedding
keywords: Coronavirus; MERS-CoV; Middle East; RT-PCR; Viral kinetics