Molecular Epidemiology of Hospital Outbreak of Middle East Respiratory Syndrome, Riyadh, Saudi Arabia, 2014

Emerg Infect Dis. 2015 Nov;21(11):1981-8. doi: 10.3201/eid2111.150944.


We investigated an outbreak of Middle East respiratory syndrome (MERS) at King Fahad Medical City (KFMC), Riyadh, Saudi Arabia, during March 29-May 21, 2014. This outbreak involved 45 patients: 8 infected outside KFMC, 13 long-term patients at KFMC, 23 health care workers, and 1 who had an indeterminate source of infection. Sequences of full-length MERS coronavirus (MERS-CoV) from 10 patients and a partial sequence of MERS-CoV from another patient, when compared with other MERS-CoV sequences, demonstrated that this outbreak was part of a larger outbreak that affected multiple health care facilities in Riyadh and possibly arose from a single zoonotic transmission event that occurred in December 2013 (95% highest posterior density interval November 8, 2013-February 10, 2014). This finding suggested continued health care-associated transmission for 5 months. Molecular epidemiology documented multiple external introductions in a seemingly contiguous outbreak and helped support or refute transmission pathways suspected through epidemiologic investigation.

Keywords: MERS; MERS-CoV; Middle East respiratory syndrome; Middle East respiratory syndrome coronavirus; Saudi Arabia; coronavirus; health care workers; molecular epidemiology; mutation; nosocomial infection; phylogeny; respiratory infections; transmission; viruses; zoonoses.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Coronavirus Infections / epidemiology*
  • Coronavirus Infections / genetics
  • Coronavirus Infections / transmission
  • Disease Outbreaks*
  • Humans
  • Iatrogenic Disease / epidemiology*
  • Molecular Epidemiology / methods*
  • Respiratory Tract Infections / epidemiology*
  • Respiratory Tract Infections / genetics
  • Respiratory Tract Infections / transmission
  • Saudi Arabia / epidemiology