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Our Perspective on MERS CoV (2013): Hospitals Wake Up!

Image of Dr. Eric Toner
Eric Toner, MD
Date posted:
May 10, 2013
Publication type:

Our Perspective on MERS CoV: May 10, 2013

Open access

News outlets in France are reporting this morning, May 10, 2013, that there are 3 suspected new cases in northern France of MERS-CoV (Middle East Respiratory Syndrome coronavirus), the proposed new name for the novel coronavirus that has so far has caused 31 confirmed cases with 18 deaths. These 3 new suspected cases are significant because they appear to involve nosocomial transmission—transmission within a healthcare setting.1,2

The New Suspected Cases

All 3 of the new suspected cases had contact with the one confirmed case in France that was reported on Wednesday, May 8. That confirmed case is a 65 year-old French male who returned from Dubai and became ill in late April. He remains hospitalized in critical condition. The 3 new suspected cases involve a hospital roommate of the 65 year-old male and 2 healthcare workers from the hospital where he is being treated. All suspected cases are currently hospitalized, and laboratory confirmation is pending.


The MERS-CoV is a cousin of the coronavirus that caused the SARS pandemic in 2003 that resulted in 8,000 cases and 775 deaths in 29 countries. In many ways this new coronavirus, the first cases of which occurred about a year ago, more and more seems to behave like the SARS virus. See the perspective of May 7, 2013.3 One of the hallmarks of SARS was the fact that approximately half of the cases involved nosocomial transmission, and most of the cases occurred in clusters that could be traced back to nosocomial outbreaks. So far there has been a cluster of confirmed and suspected cases of MERS that occurred in a hospital in Jordan in April 2012 and suspected nosocomial transmission in Saudi Arabia recently. If these 3 new cases are confirmed, they would represent the third hospital-related outbreak of MERS.

Nosocomial Spread of SARS

The reason SARS was largely a nosocomial disease was because most shedding of the virus occurred when the patient was at the peak of the illness—typically several days or more into the illness, when the patient was likely to be in the hospital. This stands in sharp contrast to influenza, for example, in which viral shedding starts before the onset of illness and is maximal in the first few days of the illness. Thus in SARS, patients were in close contact with other patients and healthcare workers when they were most contagious. The important lesson from SARS was that transmission could be blocked by appropriate use of infection control measures, including respiratory isolation of suspected patients and the use of personal protective equipment (PPE) by healthcare workers. Most nosocomial transmission of SARS resulted from unsuspected cases who were not placed in appropriate isolation, or healthcare workers who did not use PPE properly.

Another hallmark of SARS was the super-spreader phenomenon. Most people infected with SARS did not transmit the virus to anyone else. Instead, the disease was spread by a small number of people who each infected a relatively large number (sometimes dozens) of people. These patients were known as super spreaders. Super spreading is not unknown in other infectious diseases and probably occurs more than we know, but it stood out more clearly in SARS than in other recent epidemics. The mechanism of super spreading in SARS is not completely understood, but in many cases it was associated with nosocomial transmission.4

Time for Hospitals to Be Alert

What does this mean for the MERS-CoV epidemic? Human-to-human transmission of MERS-CoV has been previously documented in the imported case in Britain. If the new cases are confirmed, it means that to some extent MERS is following the same path as SARS. SARS was stopped by healthcare workers being aware of the disease, having a high index of suspicion of anyone with fever and respiratory symptoms who had recently been in an affected region, and quickly implementing infection control measures with any suspect case. Until now, all cases of MERS originated in the Middle East, but as the confirmed French case demonstrates, the virus is only a plane ride away from other parts of the world. In the 10 years since the SARS outbreak, many hospitals have become lax in their attention to respiratory precautions. These cases, whether confirmed or not, should be a wake up call.


  1. Two people in France ill after contact with coronavirus victim. Reuters. May 9, 2013. Accessed May 10, 2013.
  2. Keller G. France Probes 3 Suspected Cases of SARS-Like Virus. Associated Press. May 10, 2013. Accessed May 10, 2013.
  3. Adalja A. Perspective: MERS-CoV: Similar to SARS? UPMC Center for Health Security website. May7, 2013. Accessed May 10, 2013.
  4. Toner E, Nuzzo J. Acting on the Lessons of SARS: What Remains To Be Done? Biosecurity and Bioterrorism. 2011;9(2):169- 174.



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