What to know
- Any patient in the United States with equivocal, inconclusive, or presumptive positive MERS test results must be immediately reported to CDC, with residual specimen sent for confirmatory testing.
- State and local health departments should coordinate isolation for people with MERS and home quarantine for their contacts.
Confirmed case: Definition, reporting, and next steps
A positive Middle East respiratory syndrome coronavirus (MERS) case is a person who has laboratory confirmation of MERS-CoV infection. Confirmatory laboratory testing requires a positive MERS-CoV real-time reverse transcription polymerase chain reaction (rRT-PCR) test at CDC. A positive MERS test performed at a laboratory within the laboratory response network (LRN) is considered a presumptive positive until it can be confirmed by CDC diagnostic testing.
In accordance with the Emergency Use Authorization (EUA) instructions for use of the U.S. MERS-CoV rRT-PCR, any specimen with a MERS-CoV presumptive positive interpretation identified at a laboratory within the LRN should be shipped to CDC in accordance with the CDC-10488 test order for confirmatory testing. If an LRN laboratory has a presumptive positive test result without a residual specimen available, and a new specimen cannot be collected, please contact the CDC Emergency Operations Center.
State and local health departments should immediately contact CDC to discuss further epidemiological investigation and management of an equivocal, inconclusive, or presumptive positive test result, a confirmed case, or both.
State or local health departments should coordinate isolation for people with confirmed MERS and home quarantine for their contacts, respectively. CDC will work with health departments to determine these procedures.
Reporting MERS Persons Under Investigation (PUIs)
- All MERS PUIs who are awaiting testing or test results should remain quarantined and avoid contact with others, if possible. Any positive MERS patient should be isolated and avoid contact with others. Hospitalized patients who are PUIs or presumptive positive MERS patients should follow all recommended MERS-CoV infection controls until testing results are negative.
- State and local health departments must submit all MERS-CoV rRT-PCR results (e.g., negative, positive, inconclusive, and equivocal) via the Laboratory Response Network (LRN), in accordance with the EUA instructions for use.
- Any MERS PUI with presumptive positive MERS test results must be immediately reported to CDC, with residual specimen sent to CDC for confirmatory testing.
- CDC staff are available for epidemiologic and laboratory consultation for MERS. Contact the CDC Emergency Operations Center.
Multiple state and local public health labs offer MERS testing. Clinicians should first contact their local or state health departments to discuss MERS PUIs and testing.
Evaluation and management of close contacts
Close contacts of a confirmed case
CDC has developed an outbreak investigation protocol and related resources to help support public health partners' outbreak containment efforts in the event of a confirmed positive MERS case in the US. State health department personnel may contact the CDC Emergency Operations Center by email (eocreport@cdc.gov) or phone (770-488-7100) to access these resources.
As part of investigation of confirmed cases, close contacts[A] of a confirmed case should be actively monitored by health departments, or monitor themselves, for fever[B] or symptoms of respiratory illness for 14 days after their last exposure. State and local public health departments should strongly consider quarantining contacts during active monitoring periods. A person who develops fever [B]or symptoms of respiratory illness within 14 days following close contact[A] with a confirmed case of MERS should be tested for MERS-CoV infection.
Other contacts of the confirmed case, such as community contacts or contacts on conveyances (e.g., airplane, bus), may be considered for evaluation and testing in consultation with state and local health departments and CDC.
Clinicians and public health professionals should be aware that a wide spectrum of illness in patients with MERS has been reported, ranging from asymptomatic to severe acute respiratory illness resulting in death. Symptomatic contacts should be tested. If the patient's symptom onset was more than 14 days prior to testing, the situation should be discussed further with state and local health departments and CDC.
People who are confirmed to have MERS and who do not require hospitalization for medical reasons may isolate at home. Close contacts who are symptomatic and awaiting MERS testing or MERS testing results, and who do not require hospitalization for medical reasons, should be quarantined. All at-home isolation and quarantine decisions should be made by the state or local health department and in conjunction with healthcare providers and the CDC.
All contacts should be monitored for 14 days after last exposure. Contacts with no apparent symptoms who test positive for MERS by rRT-PCR in respiratory specimens likely pose a risk of transmission, although the magnitude and contributing factors are unclear.
Close contacts of a PUI
Healthcare providers should discuss evaluation and management of close contacts of a PUI with state and local health departments. CDC staff are available for epidemiologic and laboratory consultation for MERS. Contact the CDC Emergency Operations Center.
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 in these contacts.
State and local health department personnel may contact the CDC Emergency Operations Center by email (eocreport@cdc.gov) or by phone (770-488-7100).
Clusters of respiratory illness in which MERS should be considered
Clusters of patients with severe acute respiratory illness without recognized links to a case of MERS-CoV infection or to travelers from countries in or near the Arabian PeninsulaA should be tested for common respiratory pathogens. If the illnesses remain unexplained, healthcare providers should consider testing for MERS, in consultation with state and local health departments and CDC.
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- Fever may not be present in some patients, such as those who are very young, elderly, immunosuppressed, or taking certain medications. Clinical judgement should be used to guide testing of patients in such situations.
- Close contact is defined as a.) being within approximately 6 feet (2 meters), or within the room or care area, of a confirmed MERS case for a prolonged period of time (such as caring for, living with, visiting, or sharing a healthcare waiting area or room with a confirmed MERS case) while not wearing recommended personal protective equipment (PPE) (e.g., gowns, gloves, a NIOSH-certified disposable N95 respirator, eye protection); or b.) having direct contact with infectious secretions of a confirmed MERS case (e.g., being coughed on) while not wearing recommended PPE. See Prevention and Control for Hospitalized MERS Patients. Data to inform the definition of close contact are limited; considerations when assessing close contact include the duration of exposure (e.g., longer exposure time likely increases exposure risk) and the clinical symptoms of the person with MERS (e.g., coughing likely increases exposure risk). Special consideration should be given to those exposed in healthcare settings. Transient interactions, such as walking by a person with MERS, are not thought to constitute an exposure; however, final determination should be made in consultation with public health authorities.