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Middle East Respiratory Syndrome Coronavirus (MERS-CoV)


General Information

General InformationGeneral Information


  • emerging betacoronavirus associated with severe respiratory illness1,2
  • all cases to date are epidemiologically linked to countries in or near the Arabian Peninsula1


  • World Health Organization (WHO) revised interim case definition for reporting MERS-CoV
    • confirmed case - laboratory-confirmed MERS-CoV infection through detection of viral nucleic acid or demonstration of seroconversion in 2 samples ideally taken ≥ 14 days apart
    • probable case - defined as 1 of 3 combinations of clinical, epidemiological, and laboratory criteria
      • combination 1
        • febrile acute respiratory illness with clinical, radiologic, or histopathologic evidence of pulmonary parenchymal disease
        • MERS-CoV testing unavailable or negative on single inadequate specimen (such as, improperly handled specimen or nasopharyngeal sample without lower respiratory sample)
        • direct epidemiological link with confirmed case of MERS-CoV
      • combination 2
        • febrile acute respiratory illness with clinical, radiologic, or histopathologic evidence of pulmonary parenchymal disease
        • inconclusive MERS-CoV laboratory test (such as positive screening test on single RT-PCR or evidence of seroreactivity by single convalescent serum without confirmation)
        • traveler to or resident of Middle Eastern countries or countries where MERS-CoV is known to be circulating in dromedary camels or where human infections have recently occurred
      • combination 3
        • acute febrile illness of any severity
        • inconclusive MERS-CoV laboratory test
        • direct epidemiological link with confirmed case of MERS-CoV
      • epidemiological link with confirmed case may have occurred within 14-day period before or after illness onset in case under consideration and is defined as any of
        • close physical contact
        • working in close proximity
        • sharing classroom environment
        • joint travel in conveyance of any kind
        • cohabitation
    • References - WHO revised interim case definition 2014 July 14OpenInNew, WHO Global Alert and Response (GAR) coronavirus infectionsOpenInNew
  • Centers for Disease Control and Prevention (CDC) definition of close contact includes
    • healthcare workers or family members providing care for the patient
    • any individual with close contact with an ill person, similar to provision of care as above
    • any individual residing or visiting the same place as the patient, during the patient's period of illness
    • Reference - CDC interim guidance for health professionalsOpenInNew


General references used

  1. Bialek SR, Allen D, Alvarado-Ramy F., et al., Division of Viral Diseases, National Center for Immunization and Respiratory Diseases, CDC. 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 May 16;63(19):431-6OpenInNewfull-textOpenInNew
  2. Coleman CM, Frieman MB. Coronaviruses: important emerging human pathogens. J Virol. 2014 May;88(10):5209-12OpenInNewfull-textOpenInNew

Synthesized Recommendation Grading System for DynaMed

  • DynaMed systematically monitors clinical evidence to continuously provide a synthesis of the most valid relevant evidence to support clinical decision-making (see 7-Step Evidence-Based MethodologyOpenInNew).
  • Guideline recommendations summarized in the body of a DynaMed topic are provided with the recommendation grading system used in the original guideline(s), and allow DynaMed users to quickly see where guidelines agree and where guidelines differ from each other and from the current evidence.
  • In DynaMed (DM), we synthesize the current evidence, current guidelines from leading authorities, and clinical expertise to provide recommendations to support clinical decision-making in the Overview & Recommendations section.
  • We use the Grading of Recommendations Assessment, Development and Evaluation (GRADE)OpenInNew to classify synthesized recommendations as Strong or Weak.
    • Strong recommendations are used when, based on the available evidence, clinicians (without conflicts of interest) consistently have a high degree of confidence that the desirable consequences (health benefits, decreased costs and burdens) outweigh the undesirable consequences (harms, costs, burdens).
    • Weak recommendations are used when, based on the available evidence, clinicians believe that desirable and undesirable consequences are finely balanced, or appreciable uncertainty exists about the magnitude of expected consequences (benefits and harms). Weak recommendations are used when clinicians disagree in judgments of relative benefit and harm, or have limited confidence in their judgments. Weak recommendations are also used when the range of patient values and preferences suggests that informed patients are likely to make different choices.
  • DynaMed (DM) synthesized recommendations (in the Overview & Recommendations section) are determined with a systematic methodology:
    • Recommendations are initially drafted by clinical editors (including ≥ 1 with methodological expertise and ≥ 1 with content domain expertise) aware of the best current evidence for benefits and harms, and the recommendations from guidelines.
    • Recommendations are phrased to match the strength of recommendation. Strong recommendations use "should do" phrasing, or phrasing implying an expectation to perform the recommended action for most patients. Weak recommendations use "consider" or "suggested" phrasing.
    • Recommendations are explicitly labeled as Strong recommendations or Weak recommendations when a qualified group has explicitly deliberated on making such a recommendation. Group deliberation may occur during guideline development. When group deliberation occurs through DynaMed-initiated groups:
      • Clinical questions will be formulated using the PICO (Population, Intervention, Comparison, Outcome) framework for all outcomes of interest specific to the recommendation to be developed.
      • Systematic searches will be conducted for any clinical questions where systematic searches were not already completed through DynaMed content development.
      • Evidence will be summarized for recommendation panel review including for each outcome, the relative importance of the outcome, the estimated effects comparing intervention and comparison, the sample size, and the overall quality rating for the body of evidence.
      • Recommendation panel members will be selected to include at least 3 members that together have sufficient clinical expertise for the subject(s) pertinent to the recommendation, methodological expertise for the evidence being considered, and experience with guideline development.
      • All recommendation panel members must disclose any potential conflicts of interest (professional, intellectual, and financial), and will not be included for the specific panel if a significant conflict exists for the recommendation in question.
      • Panel members will make Strong recommendations if and only if there is consistent agreement in a high confidence in the likelihood that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. Panel members will make Weak recommendations if there is limited confidence (or inconsistent assessment or dissenting opinions) that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. No recommendation will be made if there is insufficient confidence to make a recommendation.
      • All steps in this process (including evidence summaries which were shared with the panel, and identification of panel members) will be transparent and accessible in support of the recommendation.
    • Recommendations are verified by ≥ 1 editor with methodological expertise, not involved in recommendation drafting or development, with explicit confirmation that Strong recommendations are adequately supported.
    • Recommendations are published only after consensus is established with agreement in phrasing and strength of recommendation by all editors.
    • If consensus cannot be reached then the recommendation can be published with a notation of "dissenting commentary" and the dissenting commentary is included in the topic details.
    • If recommendations are questioned during peer review or post publication by a qualified individual, or reevaluation is warranted based on new information detected through systematic literature surveillance, the recommendation is subject to additional internal review.

DynaMed Editorial Process

Special acknowledgements

  • DynaMed topics are written and edited through the collaborative efforts of the above individuals. Deputy Editors, Section Editors, and Topic Editors are active in clinical or academic medical practice. Recommendations Editors are actively involved in development and/or evaluation of guidelines.
  • Editorial Team role definitions
    Topic Editors define the scope and focus of each topic by formulating a set of clinical questions and suggesting important guidelines, clinical trials, and other data to be addressed within each topic. Topic Editors also serve as consultants for the internal DynaMed Editorial Team during the writing and editing process, and review the final topic drafts prior to publication.
    Section Editors have similar responsibilities to Topic Editors but have a broader role that includes the review of multiple topics, oversight of Topic Editors, and systematic surveillance of the medical literature.
    Recommendations Editors provide explicit review of DynaMed Overview and Recommendations sections to ensure that all recommendations are sound, supported, and evidence-based. This process is described in "Synthesized Recommendation Grading."
    Deputy Editors are employees of DynaMed and oversee DynaMed internal publishing groups. Each is responsible for all content published within that group, including supervising topic development at all stages of the writing and editing process, final review of all topics prior to publication, and direction of an internal team.

How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T902618, Middle East Respiratory Syndrome Coronavirus (MERS-CoV); [updated 2018 Nov 30, cited place cited date here]. Available from Registration and login required.


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