About Middle East Respiratory Syndrome (MERS)

Key points

  • MERS is a viral respiratory illness.
  • Most MERS cases have been detected in countries in or near the Arabian Peninsula.
  • MERS represents a very low risk to the general public in the United States.

What it is

Middle East Respiratory Syndrome (MERS) is a viral respiratory illness caused by a coronavirus called Middle East respiratory syndrome coronavirus (MERS-CoV). The virus can spread from camels to people through direct physical contact. Limited human-to-human transmission is possible. MERS has caused severe respiratory disease in most diagnosed cases, and many of those patients died. Typical symptoms include fever, cough, and shortness of breath.

Most MERS cases have been detected in countries in or near the Arabian Peninsula. However, a number of cases linked to travel have been detected in countries outside this region.

For more information about travel guidelines for your destination, visit CDC's Travelers' Health site.

Did you know?‎

CDC does not recommend that anyone change travel plans to, in, or near the Arabian Peninsula because of MERS.

Countries in or near the Arabian Peninsula that have reported MERS cases: Bahrain, Iran, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, United Arab Emirates (UAE), and Yemen.

Countries outside of the Arabian Peninsula with MERS cases linked to travel: Algeria, Austria, China, Egypt, France, Germany, Greece, Italy, Malaysia, Netherlands, Philippines, Republic of Korea, Thailand, Tunisia, Turkey, United Kingdom, and the United States.

Only two patients in the United States have ever tested positive for MERS. Both cases were in May 2014 and were among healthcare providers who lived and worked in Saudi Arabia.

Signs and symptoms

Most people with confirmed MERS-CoV infection have had severe respiratory illness. MERS symptoms usually appear 5 or 6 days after a person is exposed. However, symptoms can appear as early as 2 days and up to 14 days after exposure.

Common symptoms of MERS include:

  • Fever
  • Cough
  • Shortness of breath

Some people may also have diarrhea, nausea, or vomiting. It is also possible that someone with MERS may have only mild symptoms or no symptoms.

In most known MERS cases, the infected person developed pneumonia. Additional complications such as kidney failure have also occurred. About 3 or 4 out of every 10 people reported with a MERS infection died.

Most of the people who die from MERS had at least one preexisting medical condition. Certain conditions may increase the risk of getting severe complications from MERS. These include:

  • Diabetes
  • Cardiovascular disease, including high blood pressure
  • Chronic lung disease
  • Chronic heart disease
  • Chronic kidney disease
  • Cancer

Who is at risk

You may be at increased risk of getting MERS if you:

  • Recently (in the past 14 days) returned from travel in or near the Arabian Peninsula, and especially if you also:
    • Worked in or visited a healthcare setting
    • Had direct physical contact with camels (including touching or grooming)
    • Had close contact with a person who was sick with fever or respiratory symptoms
  • Had close contact in the past 14 days with someone who was sick with fever or respiratory symptoms of unknown cause after they had traveled in or near the Arabian Peninsula
  • Had close contact in the past 14 days with someone who has tested positive for MERS

When to call your healthcare provider‎

If you develop fever or symptoms of respiratory illness, such as cough or shortness of breath, within 14 days of the above activities, call a healthcare provider. Tell your healthcare provider about any reason you may be at increased risk for MERS.

How it spreads

The virus that causes MERS can spread through respiratory secretions, such as saliva or mucous, of infected animals or people. The MERS virus is mostly found in camels (dromedaries), and direct physical contact with camels can lead to transmission to humans. People infected through contact with camels can then spread the virus to other people. All reported person-to-person transmissions of MERS have been linked to someone who had been in or near the Arabian Peninsula.

Large MERS outbreaks from person-to-person spread have occurred in healthcare facilities treating patients with MERS. Some spread can occur in households through close contact (like sharing a bed or caring for someone who is sick). The largest known outbreak of MERS outside the Arabian Peninsula occurred in the Republic of Korea in 2015. Multiple healthcare facilities were affected by the outbreak, which was associated with a traveler returning from the Arabian Peninsula.

Researchers continue to investigate clusters of MERS cases to better understand how the virus spreads.


No vaccine exists to protect people against MERS. CDC's Respiratory Virus Guidance provides practical recommendations and information to help people lower health risks from respiratory viral illnesses.

For travelers, the World Health Organization recommends:

  • Wash your hands before and after touching camels.
  • Avoid drinking raw camel milk or camel urine or eating meat (including camel meat) that has not been properly cooked.
  • If you are someone at higher risk for severe MERS illness, avoid close contact with camels.


No specific antiviral treatment is recommended for MERS. People with MERS often receive supportive medical care and care to help relieve symptoms.