Middle East Respiratory Syndrome (MERS)

Photo: MERS-CoV particles

There have been no MERS cases in the United States since May 2014. The risk of MERS to the general public in this country remains very low. CDC and other public health partners continue to closely monitor the MERS situation.

Since MERS first emerged in the Arabian Peninsula in 2012, CDC has been working with global partners to better understand the nature of the virus, including how it affects people, and how it spreads. We recognize the potential for MERS-CoV to spread further and cause more cases in the United States and globally, and we are taking actions in preparation. Learn more.

MERS in the U.S.

Only two patients in the U.S. have ever tested positive for MERS-CoV infection—both in May 2014—while more than 1,300 people have tested negative. In May 2014, CDC confirmed two cases of MERS in the United States—one in Indiana, the other in Florida. Both cases were among healthcare providers who lived and worked in Saudi Arabia. Both traveled to the U.S. from Saudi Arabia, where they are believed to have been infected. Both were hospitalized in the U.S. and later discharged after fully recovering.

Understanding the Virus

Middle East Respiratory Syndrome (MERS) is a viral respiratory illness that is new to humans. It was first reported in Saudi Arabia in 2012. The virus that causes MERS is called Middle East Respiratory Syndrome Coronavirus (MERS-CoV). Coronaviruses are common viruses that most people get at some time in their life. Human coronaviruses usually cause mild to moderate cold-like illnesses. However, MERS-CoV is different from any other coronavirus previously found in people.

MERS-CoV likely came from an animal source in the Arabian Peninsula. Researchers have found MERS-CoV in camels from several countries. We don’t know whether camels are the only source of the virus, but studies continue to provide evidence that camel infections play a role in human infection with MERS-CoV. However, more information is needed.

MERS Symptoms

MERS can cause mild to severe respiratory symptoms or no symptoms at all. Symptoms can include fever, cough, and shortness of breath. Other symptoms can include diarrhea, nausea/vomiting, pneumonia, and kidney failure. MERS can be deadly. About 3 or 4 out of every 10 patients reported with MERS have died.

How MERS Spreads

MERS-CoV is thought to spread from an infected person to others though respiratory secretions, such as coughing. However, we don’t fully understand the precise ways the virus spreads.

Protect Yourself from Respiratory Illnesses

There is currently no vaccine to prevent MERS-CoV infection. CDC routinely advises Americans to help protect themselves from respiratory illnesses by

  • washing hands often,
  • avoiding close contact with people who are sick,
  • avoiding touching their eyes, nose, and mouth with unwashed hands, and
  • disinfecting frequently touched surfaces.

MERS and Travel

CDC does not recommend that anyone change their travel plans because of MERS. Travelers should practice general hygiene precautions such as frequent handwashing; avoiding touching your eyes, nose, and mouth; and avoiding contact with sick people.

The World Health Organization considers certain groups to be at high risk for severe MERS. These groups include people with diabetes, kidney failure, or chronic lung disease, and people who have weakened immune systems. The World Health Organization recommends that these groups take additional precautions:

  • avoid contact with camels
  • do not drink raw camel milk or raw camel urine
  • do not eat undercooked meat, particularly camel meat

See MERS in the Arabian Peninsula for more information on travel notices.

Learn more about MERS in the U.S.