Middle East Respiratory Syndrome Coronavirus (MERS-CoV)

Paul G. Auwaerter, M.D., Jaffar A. Al-Tawfiq, M.D.


  • MERS-CoV is a coronavirus, newly described virus first isolated in 2012.
    • β-coronavirus: not the same virus as SARS, but related.
    • Similar to other coronavirus described in bats.
    • MERS-CoV: dromedary camels clearly established as a host, dating at least to early 1990s. Also seen in bats.
  • Believed to be mostly a respiratory pathogen in humans, as coronavirus cause disease ranging from common cold to rarely severe pulmonary illness.


  • All cases (Dec 2015) traced to regions in or near Arabian Peninsula.
    • Countries in Arabian Peninsula with confirmed cases: Saudi Arabia, United Arab Emirates (UAE), Qatar, Oman, Jordan, Kuwait, Iran, Egypt, Yemen, Lebanon.
      • Countries with travel-related cases (imported): U.S. (2 cases), UK, France, Tunisia, Italy, Malaysia, S. Korea (also indigenous transmission), Germany, Netherlands, Greece, Turkey, Austria, China, Philippines, Thailand, Algeria.
      • Human-human spread, likely requiring close contact; nosocomially acquired cases reflect inadequate infection control practices, overcrowding and failure to recognize.
      • Asymptomatic infections may contribute to transmission.
  • Symptoms: non-specific: fever, cough and dyspnea.
    • Most cases identified to date were severe and requiring hospitalization.
      • Most fatalities have been described in hospitalized patients with comorbidities.
      • Spectrum of illness: ranging from asymptomatic to flu-like illness to severe, SARS-like infection with multiorgan failure.
    • Gastrointestinal symptoms: diarrhea, vomiting and abdominal pain (up to 30%).
    • Mortality: 36% in cases reported to WHO.
  • Consider to place patient(s) under investigation: guidance from the CDC[15].
    • An acute respiratory infection, which may include fever (≥ 38°C , 100.4°F) and cough; AND
    • Suspicion of pulmonary parenchymal disease (e.g., pneumonia or acute respiratory distress syndrome based on clinical or radiological evidence of consolidation) AND
      • History of travel from the Arabian Peninsula (or neighbors, plus Korea) within 14d AND
      • No explanation by an other infection or etiology, including all clinically indicated tests for community-acquired pneumonia
    • Also, the following people may be considered for evaluation:
      • People who develop severe acute lower respiratory illness of known etiology within 14 days after travel from the Arabian Peninsula or neighboring countries but do not respond to appropriate therapy; OR
      • People who develop severe acute lower respiratory illness who are close contacts of a symptomatic traveler who developed fever and acute respiratory illness within 14 days after travel from the Arabian Peninsula or neighboring countries.
    • U.S. reporting short form (link): http://www.cdc.gov…


  • Laboratory: molecular diagnostics are the method of choice for MERS-CoV.
    • Real-time reverse transcription–PCR assay:
      • May test respiratory, blood and stool specimens. Lower respiratory samples yield better results than upper respiratory samples.
      • Available through U.S. state health departments.
    • Serology: developed, but not yet widely used for clinical care or diagnosis.
    • Viral culture: should only be performed in specialized laboratories.
  • Additional details regarding updated information and evaluation from CDC.



  • Potential cases should be reported immediately to local and/or state health department.
  • Antiviral therapy: none known to be effective.
    • Convalescent serum with high neutralizing antibody titer against MERS-CoV may be of use as well as any specific monoclonal antibodies (not available).
  • Supportive care advised, including mechanical ventilation.
  • Use of antivirals is non-conclusive.

Special Considerations

  • All contacts of potential or confirmed MERS-CoV infected patient should be monitored for development of respiratory symptoms.
  • Infection control:
    • Patients should be placed in airborne infection isolation (AII) room (negative pressure); if unavailable, consider transfer of patient to facility that has capabilities.
    • Personal protection equipment (N-95 masks) and environmental cleaning.
    • Additional details: http://www.cdc.gov…


  • Given lack of therapeutics or vaccines so far, prevention is critical since MERS-CoV appears endemic with ongoing cases.
  • No specific travel recommendations currently (Dec 2015): http://www.cdc.gov…
    • Travelers to Hajj: consider protection from respiratory illness and avoid contacts with.
    • Ill travelers from Arabian peninsula should be reported to CDC: http://www.cdc.gov…
  • Respiratory prevention (general)
    • Hand washing: soap and water for 20 seconds. If soap/water unavailable, use alcohol-based sanitizers.
    • Avoid touching face with unwashed hands.
    • Avoid close contact such as kissing, sharing cups, or sharing eating utensils with sick people.
    • Clean and disinfect frequently touched surfaces, such as toys and doorknobs.
    • Practice cough etiquette.
  • See infection control section above.


  • Mortality 36% in cases reported to WHO.
    • High rates seen especially in older patients and those with comorbidities.
      • Death usually due to multiorgan failure.
      • Higher mortality in those requiring ICU admission.


  • Appears to be SARS-like illness but with less efficacy causing human-human spread.
  • For most update information visit the following websites:

Basis for recommendation

  1. Bialek SR, Allen D, Alvarado-Ramy F, et al. First Confirmed Cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) Infection in the United States, Updated Information on the Epidemiology of MERS-CoV Infection, and Guidance for the Public, Clinicians, and Public Health Authorities - May 2014. MMWR Morb Mortal Wkly Rep. 2014;63(19):431-6.  [PMID:24827411]

    Comment: Report of first two cases of imported MERS-CoV into US. Report also summarizes current recommendations regarding case description/patient evaluation, specimen procurement and testing.

  2. World Health Organization. Coronavirus infections; Global Alert and Response.http://www.who.int/csr/disease/coronavirus_infections/en/index.html (accessed 10/19/2015)

    Comment: Coordinating site including MERS-CoV, SARS and other coronaviruses with public health implications. Includes link to interim case definition for MERS-CoV infection.

  3. Centers for Disease Control and Prevention; Coronavirus--Middle East Respiratory Syndrome (MERS); http://www.cdc.gov/coronavirus/mers/ (Oct 2015)

    Comment: Guidance from the CDC Visit URL link for most up to date information.


  1. Zumla A, Hui DS, Perlman S. Middle East respiratory syndrome. Lancet. 2015;386(9997):995-1007.  [PMID:26049252]

    Comment: Mortality among cases reported so far = ~ 40% including both community- and hospital-acquired cases. More severe cases seen especially in patients with co-morbidities. Now into third year, it appears to be endemic and therefore a low-level but persistent public health threat.

  2. Corman VM, Albarrak AM, Omrani AS, et al. Viral Shedding and Antibody Response in 37 Patients With Middle East Respiratory Syndrome Coronavirus Infection. Clin Infect Dis. 2015.  [PMID:26565003]

    Comment: First report of a large patient population summarizing MERS-CoV kinetics and antibody response. The study shows the kinetics of the virus in upper and lower respiratory tract, stool, urine and blood samples.

  3. Drosten C, Muth D, Corman VM, et al. An observational, laboratory-based study of outbreaks of middle East respiratory syndrome coronavirus in Jeddah and Riyadh, kingdom of Saudi Arabia, 2014. Clin Infect Dis. 2015;60(3):369-77.  [PMID:25323704]

    Comment: Report from the Kingdom of Saudi Arabia with the most cases, and uptick in Spring 2014 (and again ongoing 2015). Viral studies don’t suggest virus is mutating and appear consistent in outbreaks and noscomial transmission.

  4. Oboho IK, Tomczyk SM, Al-Asmari AM, et al. 2014 MERS-CoV outbreak in Jeddah--a link to health care facilities. N Engl J Med. 2015;372(9):846-54.  [PMID:25714162]

    Comment: Of 2014 cases in KSA, most had links to hospital care implicating transmission in an arena where opportunities for prevention exist.

  5. Al-Tawfiq JA, Memish ZA. Infection control measures for the Prevention of MERS Coronavirus Transmission in Healthcare settings. Expert Rev Anti Infect Ther. 2015.  [PMID:26687211]

    Comment: This is a summary of infection control and prevention of MERS transmission in healthcare settings.

  6. Al-Tawfiq JA, Memish ZA. Managing MERS-CoV in the healthcare setting. Hosp Pract (1995). 2015;43(3):158-63.  [PMID:26224424]

    Comment: This is a concise review summarizing different aspects of MERS in healthcare setting including clinical presentation and management.

  7. Al-Tawfiq JA, Memish ZA. Middle East respiratory syndrome coronavirus: transmission and phylogenetic evolution. Trends Microbiol. 2014;22(10):573-9.  [PMID:25178651]

    Comment: This review shed lights on the different aspects of the transmission and phylogenetic evolution of MERS-CoV.

  8. Al-Tawfiq JA, Hinedi K, Ghandour J, et al. Middle East Respiratory Syndrome-Coronavirus (MERS-CoV): a case-controlstudy of hospitalized patients. Clin Infect Dis. 2014.  [PMID:24723278]

    Comment: Report from the Kingdom of Saudi Arabia examines 17 cases and 82 controls. Cases were more likely to have high BMI, normal WBC count on admission and interstitial infiltrates along with high moratligy rate (76% v. 15%, p < 0.001).

  9. Briese T, Mishra N, Jain K, et al. Middle East Respiratory Syndrome Coronavirus Quasispecies That Include Homologues of Human Isolates Revealed through Whole-Genome Analysis and Virus Cultured from Dromedary Camels in Saudi Arabia. MBio. 2014;5(3).  [PMID:24781747]

    Comment: Sequence data from human cases and samples from dromedary camels are identical (in Saudi Arabia), suggesting that camels are indeed a reservoir (known from other studies) and source of some spread to humans.

  10. Al-Tawfiq JA, Memish ZA. Middle East respiratory syndrome coronavirus: epidemiology and disease control measures. Infect Drug Resist. 2014;7:281-7.  [PMID:25395865]

    Comment: This review summarizes the epidemiology and different strategies for the control of the virus.

  11. Assiri A, Al-Tawfiq JA, Al-Rabeeah AA, et al. Epidemiological, demographic, and clinical characteristics of 47 cases of Middle East respiratory syndrome coronavirus disease from Saudi Arabia: a descriptive study. Lancet Infect Dis. 2013.  [PMID:23891402]

    Comment: Most patients diagnosed to date have had healthcare involvement and hence co-morbidities. Patients were mostly adults in the 47 described (46 adults, one child) with laboratory-confirmed MERS-CoV disease were identified; 36 (77%) were male (male:female ratio 3·3:1). 28 patients died, a 60% case-fatality rate. The case-fatality rate rose with increasing age. Only two of the 47 cases were previously healthy; most patients (45 [96%]) had underlying co-morbid medical disorders, including diabetes (32 [68%]), hypertension (16 [34%]), chronic cardiac disease (13 [28%]), and chronic renal disease (23 [49%]).
    Gastrointestinal symptoms were noted in a significant minority including diarrhea, vomiting and abdominal pain.

  12. Centers for Disease Control and Prevention (CDC). Update: Recommendations for Middle East respiratory syndrome coronavirus (MERS-CoV). MMWR Morb Mortal Wkly Rep. 2013;62(27):557.  [PMID:23842446]

    Comment: Initial recommendations for investigating potential cases.
    Rating: Important

  13. Perlman S, McCray PB. Person-to-Person Spread of the MERS Coronavirus - An Evolving Picture. N Engl J Med. 2013;369(5):466-7.  [PMID:23902487]

    Comment: Outbreak in Al-Hasa, part of eastern Saudi Arabia implicates direct person-to-person spread.

  14. Assiri A, McGeer A, Perl TM, et al. Hospital Outbreak of Middle East Respiratory Syndrome Coronavirus. N Engl J Med. 2013;369(5):407-416.  [PMID:23782161]

    Comment: Clearly implicating the potential for MERS to cause serious spread of disease in closer quarters such as hospitals, an outbreak in an eastern province of Saudi Arabia (spring 2013) with 21/23 cases due to person-person spread in healthcare environments. Mortality rate was 65% which may speak to patients with pre-existing illness acquiring.

  15. Zaki AM, van Boheemen S, Bestebroer TM, et al. Isolation of a novel coronavirus from a man with pneumonia in Saudi Arabia. N Engl J Med. 2012;367(19):1814-20.  [PMID:23075143]

    Comment: First description of virus, first called HCoV-EMC but now referred to as MERS-CoV, and related but not the cause of SARS, a related coronavirus.

  16. Müller MA, Raj VS, Muth D, et al. Human coronavirus EMC does not require the SARS-coronavirus receptor and maintains broad replicative capability in mammalian cell lines. MBio. 2012;3(6).  [PMID:23232719]

    Comment: Investigators help confirm that this is a sister virus to SARS, and that virus appears to efficiently replicate in cell lines of human, pig and bat origin.

  17. Memish ZA, Al-Tawfiq JA, Alhakeem RF, et al. Middle East respiratory syndrome coronavirus (MERS-CoV): A cluster analysis with implications for global management of suspected cases. Travel Med Infect Dis. 2015;13(4):311-4.  [PMID:26211569]

    Comment: This study summarizes the implication of global MERS cases with links between cases in Saudi Arabia and Qatar.

  18. Al-Tawfiq JA, Zumla A, Memish ZA. Travel implications of emerging coronaviruses: SARS and MERS-CoV. Travel Med Infect Dis. 2014;12(5):422-8.  [PMID:25047726]

    Comment: This is a nice review of travel implications with comparisons between SARS and MERS-CoV.

Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a sample topic from the Johns Hopkins ABX Guide.

To view other topics, please or purchase a subscription.

Official website of the Johns Hopkins Antibiotic (ABX), HIV, Diabetes, and Psychiatry Guides, powered by Unbound Medicine. Johns Hopkins Guide App for iOS, iPhone, iPad, and Android included. Complete Product Information.

Last updated: February 1, 2016