Interim Guidance for Health Professionals
Healthcare professionals should evaluate for MERS-CoV infection, patients in the U.S. who meet the following criteria:
See the Case Definitions for more information.
Patients with lower respiratory illness should also be evaluated for common causes of community-acquired pneumonia3, guided by clinical presentation and epidemiologic and surveillance information. For these patients, testing for MERS-CoV and other respiratory pathogens can be done simultaneously. Positive results for another respiratory pathogen (e.g., influenza) should not necessarily preclude testing for MERS-CoV because co-infection can occur.
CLOSE CONTACTS OF A CONFIRMED OR PROBABLE CASE
Close contacts2 of a confirmed or probable case of MERS while the case was ill should be evaluated in consultation with state and local health departments. Other contacts of the ill person, such as community contacts or contacts on conveyances (e.g., airplane, bus), should also be evaluated in consultation with state and local health departments.
Close contacts2 of a confirmed or probable case, if not using recommended infection control precautions (e.g., appropriate use of personal protective equipment), are at increased risk and should be evaluated and monitored by healthcare professionals with a higher index of suspicion to detect MERS-CoV infection. The spectrum of illness due to MERS-CoV infection is incompletely defined. Although most reported cases have had severe acute lower respiratory illness, mild and asymptomatic infections have been reported and in some cases, diarrhea preceded respiratory symptoms. Testing nasopharyngeal and oropharygeal swabs by rRT-PCR to detect MERS-CoV should be considered on initial evaluation, regardless of the presence or nature of symptoms. Healthcare professionals should carefully monitor for the appearance of fever (T>100°F) or respiratory symptoms within 14 days following the close contact, as one of these signs would meet the criteria for a patient under investigation (PUI). Other early symptoms have included headache, chills, myalgia, nausea/vomiting and diarrhea. Symptomatic contacts should be evaluated and, depending on their clinical history and presentation, considered for more extensive MERS-CoV testing, including rRT-PCR testing of lower respiratory and serum specimens, and possibly MERS-CoV serology, especially if symptom onset was more than 14 days prior.
Close contacts2 who are ill and being evaluated for MERS-CoV infection and do not require hospitalization for medical reasons may be cared for and isolated in their home. (Isolation is defined as the separation or restriction of activities of an ill person with a contagious disease from those who are well). For asymptomatic close contacts2 who are being evaluated for MERS-CoV, the possible benefit of home quarantine or other measures, such as wearing masks, is uncertain due to lack of information about transmissibility from persons with asymptomatic infection. Asymptomatic contacts who test positive by PCR, especially in respiratory specimens or serum, likely pose a risk of transmission, although the magnitude and contributing factors are unknown. Providers should contact their state or local health department to discuss home isolation, home quarantine or other measures for close contacts, especially for patients who test positive, and to discuss criteria for discontinuing any such measures. Recommendations may be modified as more data become available. For more information, see CDC’s Interim Home Care and Isolation Guidance for MERS-CoV.
CLOSE CONTACTS OF A PUI
Evaluation and management of close contacts2 of a PUI should be discussed with state and local health departments. Close contacts of a PUI should monitor themselves for fever and respiratory illness and seek medical attention if they become ill within 14 days after contact. Healthcare providers should consider the possibility of MERS.
Clusters4 of patients with severe acute respiratory illness (e.g., fever and pneumonia requiring hospitalization) without recognized links to a case of MERS-CoV infection or to travelers from countries in or near the Arabian Peninsula should be evaluated for common respiratory pathogens.3 If the illnesses remain unexplained, providers should consider testing for MERS-CoV, in consultation with state and local health departments.
Healthcare professionals should immediately report to their state or local health department any person being evaluated for MERS-CoV infection if they meet the criteria for a patient under investigation (PUI). Health departments should immediately report PUIs to CDC using the MERS PUI short form below.
- Middle East Respiratory Syndrome (MERS) Patient Under Investigation (PUI) Short Form
- (In Arabic)
- (In Urdu)
Health departments should send completed investigation short forms by FAX to CDC at 770-488-7107 or attach the short form to an e-mail to firstname.lastname@example.org (subject line: MERS Patient Form).
To date, limited information is available on the pathogenic potential and transmission dynamics of MERS-CoV. To increase the likelihood of detecting MERS-CoV infection, CDC recommends collecting multiple specimens from different sites at different times after symptom onset. For more information, see CDC’s Interim Guidelines for Collecting, Handling, and Testing Clinical Specimens from PUIs for MERS-CoV. In a PUI, CDC strongly recommends testing a lower respiratory specimen (e.g., sputum), a nasopharygeal/oropharygeal swab, and serum, via the CDC MERS-CoV rRT-PCR assay. If symptom onset was more than 14 days prior, CDC also strongly recommends additional testing of a serum specimen via the CDC MERS-CoV serologic assay.
Many state health department laboratories are approved for MERS-CoV testing using CDC’s MERS-CoV rRT-PCR assay. Contact your state health department to notify them of PUIs and to request MERS-CoV testing. If your state health department is unable to test, contact CDC’s EOC at 770-488-7100.
Appropriate infection-control measures should be used while managing patients, including specimen collection from PUIs or who have probable or confirmed MERS-CoV infections. For CDC guidance on MERS-CoV infection control in healthcare settings, see Interim Infection Prevention and Control Recommendations for Hospitalized Patients with MERS-CoV. For CDC interim guidance to prevent MERS-CoV from spreading in homes and communities in the U.S., see Interim Home Care and Isolation Guidance for MERS-CoV.
A wide clinical spectrum of MERS-CoV infection has been reported ranging from asymptomatic infection to acute upper respiratory illness, and rapidly progressive pneumonitis, respiratory failure, septic shock and multi-organ failure resulting in death. Most MERS-CoV cases have been reported in adults (median age approximately 50 years, male predominance), although children and adults of all ages have been infected. Most hospitalized MERS-CoV patients have had chronic co-morbidities. Among confirmed MERS-CoV cases reported to date, the case fatality proportion is approximately 28-30%.
Limited clinical data for MERS-CoV patients are available; most published clinical information to date is from critically ill patients. At hospital admission, common signs and symptoms include fever, chills/rigors, headache, non-productive cough, dyspnea, and myalgia. Other symptoms can include sore throat, coryza, nausea and vomiting, dizziness, sputum production, diarrhea, vomiting, and abdominal pain. Atypical presentations including mild respiratory illness without fever and diarrheal illness preceding development of pneumonia have been reported. Patients who progress to requiring admission to an intensive care unit (ICU) often have a history of a febrile upper respiratory tract illness with rapid progression to pneumonia within a week of illness onset.
The median incubation period for secondary cases associated with limited human-to-human transmission is approximately 5 days (range 2-13 days). In patients with community-acquired MERS-CoV infection who are hospitalized with more severe disease, the median time from illness onset to hospitalization is approximately 4 days. In critically ill patients, the median time from onset to intensive care unit (ICU) admission is approximately 5 days, and median time from onset to death is approximately 12 days. In one series of 12 ICU patients, the median duration of mechanical ventilation was 16 days, and median ICU length of stay was 30 days, with 58% mortality at 90 days.
Laboratory findings at admission may include leukopenia, lymphopenia, thrombocytopenia, and elevated lactate dehydrogenase levels. Radiographic findings may include unilateral or bilateral patchy densities or opacities, interstitial infiltrates, consolidation, and pleural effusions. Rapid progression to acute respiratory failure, acute respiratory distress syndrome (ARDS), refractory hypoxemia, and extrapulmonary complications (acute kidney injury requiring renal replacement therapy, hypotension requiring vasopressors, hepatic inflammation, septic shock) has been reported.
Co-infection with other respiratory viruses and a few cases of co-infection with community-acquired bacteria at admission has been reported; nosocomial bacterial and fungal infections have been reported in mechanically-ventilated patients. MERS-CoV virus can be detected with higher viral load and longer duration in the lower respiratory tract compared to the upper respiratory tract, and has been detected in feces, serum, and urine. However, very limited data are available on the duration of respiratory and extrapulmonary MERS-CoV shedding.
No specific treatment for MERS-CoV infection is currently available. For more information, see theWorld Health Organization guidance for clinical management of MERS-CoV patients [12 pages].