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Learn About Middle Eastern Respiratory Syndrome (MERS)

Middle Eastern Respiratory Syndrome, or MERS, is a viral infection that causes a severe lung infection with symptoms of fever, cough and shortness of breath. The disease was first reported in Saudi Arabia in 2012 and as of 2018 has only been found twice in the U.S.

Key Facts

  • MERS is caused by a virus known as Middle East Respiratory Syndrome Coronavirus (MERS-CoV). It is spread from person to person when in close contact.
  • Most cases have been found in Saudi Arabia, where the virus originated. Outbreaks in other countries have been traced back to infected individuals returning from travel to the Middle East.
  • The main symptoms of MERS are fevers, cough, shortness of breath, body pain, vomiting, diarrhea and muscle pain.
  • Around one-third of patients diagnosed with MERS have died.

What Is MERS?

MERS is caused by a virus in the coronavirus family, and the syndrome is also called MERS-Coronavirus (MERS-CoV). MERS-CoV causes flu-like symptoms and pneumonia in humans. It was first seen in Saudi Arabia in 2012 in a person who was admitted to the hospital with lung infection and kidney failure. Thereafter, it was identified in other people who lived or traveled to the Arabian Peninsula and in those who traveled to Saudi Arabia. More recently, an outbreak was detected that affected 180 people in the Republic of Korea. Only two cases of MERS have been reported in the United States, both in healthcare workers who had recently traveled to Saudi Arabia. Overall, more than 20 countries worldwide have reported cases of MERS. Details of those countries can be found on the World Health Organization website.

How Does MERS Affect Your Body?

The MERS virus, MERS-CoV, causes respiratory, or lung-related, illness. It may cause severe pneumonia and lung failure in some people, requiring admission to the hospital. It may also affect other parts of the body, causing dehydration (loss of body fluid) and kidney failure due to vomiting and diarrhea.

How Serious Is MERS?

According the Centers for Disease Control and Prevention (CDC), 3 to 4 out of every 10 patients diagnosed with MERS have died. Most of those who died also had underlying health problems before they became infected with MERS. Some patients infected with MERS-CoV have only mild symptoms or even no symptoms at all, but it is very important to monitor these milder cases closely for any worsening disease.

    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.


    Page Last Updated: July 23, 2019

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