Middle East Respiratory Syndrome (MERS)
Q: What is Mers?
A: Middle East Respiratory Syndrome (MERS) is a viral respiratory illness. Learn about MERS.
Q: Why is it sometimes called MERS-CoV?
A: MERS-CoV is the acronym for Middle East Respiratory Syndrome Coronavirus, the virus that causes MERS. When referring to the virus and not the illness, CDC uses MERS-CoV. When referring to the illness, CDC uses MERS. The virus was first reported in 2012 in Saudi Arabia. It is different from any other coronaviruses that have been found in people before.
Countries with Lab-Confirmed MERS Cases
Countries in or near the Arabian Peninsula with MERS cases: Bahrain, Iran, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, United Arab Emirates (UAE), and Yemen.
Countries outside of the Arabian Peninsula with travel-associated MERS cases: Algeria, Austria, China, Egypt, France, Germany, Greece, Italy, Malaysia, Netherlands, Philippines, Republic of Korea, Thailand, Tunisia, Turkey, United Kingdom (UK), and United States of America (USA).
Q: What is the source of MERS-CoV?
A: We don’t know for certain where the virus came from. However, it likely came from an animal source. In addition to humans, MERS-CoV has been found in camels in several countries. It appears that some people became infected after contact with camels, although more information is needed to figure out the possible role that camels and other animals may play in the transmission of MERS-CoV.
Q: What are the symptoms and complications that MERS can cause?
A: Read about MERS symptoms and complications.
Q: How does the virus spread?
A: Learn about how MERS-CoV spreads.
Q: Has anyone in the United States gotten infected?
A: Yes, two patients in the U.S. tested positive for MERS-CoV infection, both in May 2014. Get the most up-to-date information about MERS in the U.S.
Q: What is CDC doing about MERS?
A: CDC works 24/7 to protect people’s health. It is the job of CDC to be concerned and move quickly whenever there is a potential public health problem. CDC continues to closely monitor the MERS situation globally. CDC is working with the World Health Organization and other partners to better understand the virus, how it spreads, the source, and risks to the public’s health. We recognize the potential for MERS-CoV to spread further and cause more cases in the United States and globally. In preparation for this, we have:
- Continued to collaborate with international partners on epidemiologic and laboratory studies to better understand MERS
- Improved the way we collect data about MERS cases
- Increased lab testing capacity in states to detect cases
- Developed guidance and tools for health departments to conduct public health investigations when MERS cases are suspected or confirmed
- Provided recommendations for healthcare infection control and other measures to prevent disease spread
- Provided guidance for flight crews, Emergency Medical Service (EMS) units at airports, and U.S. Customs and Border Protection (CPB) officers about reporting ill travelers to CDC
- Disseminated up-to-date information to the general public, international travelers, and public health partners
- Used Advanced Molecular Detection (AMD) methods to sequence the complete virus genome on specimens from cases to help evaluate and further describe the characteristics of MERS-CoV. (See U.S. MERS story: Decoding MERS Coronavirus: AMD Provides Quick Answers.)
A: The MERS situation in the U.S. represents a very low risk to the general public in this country. Only two patients in the U.S. have tested positive for MERS-CoV infection—both in May 2014 after recently traveling from Saudi Arabia—while more than 800 have tested negative. CDC continues to closely monitor the situation. Read to find out if you are at increased risk for MERS-CoV infection.
Q: How can I help protect myself?
A: Visit the MERS prevention and treatment page to learn about how to protect yourself from respiratory illnesses, like MERS.
Also see Interim Guidance for Preventing MERS-CoV from Spreading in Homes and Communities, intended for caregivers, household members, and other close contacts of people confirmed to have, or being evaluated for, MERS-CoV infection.
Q: What should I do if I had close contact with someone who has MERS?
A: If you have had close contact (1) with a confirmed MERS case within the last 14 days without using the recommended infection control precautions, you should contact a healthcare provider for an evaluation. See People Who May Be at Increased Risk for MERS.
It’s important to note, however, that most people who had close contact with someone who had MERS did not get infected or become ill. We are still learning about MERS-CoV and how it spreads.
Q: Can I still travel to the Arabian Peninsula or neighboring countries where MERS cases have occurred?
A: Yes, read CDC’s travel notices on MERS in the Arabian Peninsula. (2)
Q: What if I recently traveled to the Arabian Peninsula or neighboring countries and got sick?
A: If you develop a fever (3) and symptoms of respiratory illness, such as cough or shortness of breath, within 14 days after traveling from countries in or near the Arabian Peninsula (2), you should call ahead to a healthcare provider and mention your recent travel. Until your healthcare provider says it’s okay, stay home from work or school and delay future travel to reduce the possibility of spreading illness to others. See People Who May Be at Increased Risk for MERS.
Q: What should I do if I had close contact with a recent traveler from the Arabian Peninsula?
A: If you have had close contact (1) with someone within 14 days after they traveled from a country in or near the Arabian Peninsula (2), and the traveler has/had fever (3) and symptoms of respiratory illness, such as cough or shortness of breath, you should monitor your health for 14 days, starting from the day you were last exposed to the ill person. If you develop fever (3) and symptoms of respiratory illness, such as cough or shortness of breath, you should call ahead to a healthcare provider and mention your recent contact with the traveler. Until your healthcare provider says it’s okay, stay home from work or school and delay future travel to reduce the possibility of spreading illness to others. See People Who May Be at Increased Risk for MERS.
Q: Does the U.S. detain arriving travelers who are believed to have MERS?
A: CDC may detain individuals arriving in the U.S. or traveling between states who are believed to be infected with a quarantinable disease, including MERS, as of July 31, 2014, per amended U.S. Executive Order 13295. “Isolation” is used to separate ill people who have a contagious disease from those who are healthy; “quarantine” is used to separate and restrict the movement of well people who may have been exposed to a contagious disease to see if they become ill. See About Quarantine and Isolation.
Q: Is there a vaccine?
A: Currently, there is no vaccine available to protect against MERS.
Q: What are the treatments?
A: Learn about MERS treatment.
Q:Should I be tested for MERS?
A: If you develop a fever (3) and symptoms of respiratory illness, such as cough or shortness of breath, within 14 days after travel from a country in or near the Arabian Peninsula (2), or if you have had close contact (1) with someone showing these symptoms who has recently traveled from this area, you should call ahead to a healthcare provider and mention your recent travel or close contact. Your healthcare provider will work with your state’s public health department to test you for MERS.
Q:How do you test a person for MERS?
A: There are two main ways to determine if a person is, or has been, infected with MERS-CoV.
- One type of test, conducted by state and CDC labs, is called PCR, or polymerase chain reaction, assays.
- PCR assays are done with respiratory, serum, or stool samples and can quickly indicate if a person has an active infection with MERS-CoV.
- A second type of test, conducted by CDC lab, is called serology testing.
- Serology testing uses serum samples and is designed to look for antibodies to MERS-CoV that would indicate a person had been previously infected with the virus and developed an immune response or has an active MERS-CoV infection for approximately 14 or more days.
- Serology for MERS-CoV often includes three separate tests – (1) a screening test called ELISA or enzyme-linked immunosorbent assay, (2) a confirmatory test called IFA or Immunofluorescent assay, and (3) a slower, but more definitive confirmatory test called the neutralizing antibody assay.
Q: What should healthcare providers and health departments do?
A: For recommendations and guidance on the case definitions; infection control, including personal protective equipment guidance; home care and isolation; case investigation; and specimen collection and shipment, see Information for Healthcare Professionals.
Q: Is MERS-CoV the same as the SARS virus?
A: No. MERS-CoV is not the same coronavirus that caused severe acute respiratory syndrome (SARS) in 2003. However, like the SARS virus, MERS-CoV is most similar to coronaviruses found in bats. CDC is still learning about MERS.
- 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 or PPE (e.g., gowns, gloves, 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 personal protective equipment. See CDC’s Interim Infection Prevention and Control Recommendations for Hospitalized Patients with MERS. 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. For detailed information regarding healthcare personnel (HCP) please review CDC Interim U.S. Guidance for Monitoring and Movement of Persons with Potential Middle East Respiratory Syndrome (MERS-CoV) Exposure. 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.
- Countries considered in the Arabian Peninsula and neighboring include: Bahrain,; Iraq; Iran; Israel, the West Bank, and Gaza; Jordan; Kuwait; Lebanon; Oman; Qatar, Saudi Arabia; Syria; the United Arab Emirates (UAE); and Yemen.
- 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.
- CDC Fact Sheet – Information about MERS [2 pages]
- Frequently Asked Questions on Middle East Respiratory Syndrome Coronavirus (MERS-CoV)
- World Health Organization