Understanding Middle East Respiratory Syndrome (MERS)

Middle East respiratory syndrome (MERS) is an illness that affects your respiratory system. It is caused by a common type of virus called coronavirus (MERS-CoV). MERS-CoV is related to SARS-CoV-2, the virus that causes COVID-19. But MERS-CoV often causes a milder infection. It's also much less contagious (spread by an infected person). This virus generally causes a moderately severe respiratory illness. But in some cases, the symptoms are very severe and can lead to death.

MERS was first reported in 2012. It has been mostly found in countries in the Middle East, including Saudi Arabia, Jordan, and Yemen. Some cases have also been found in Europe and in people who have recently traveled to the Middle East. Only a few cases have been reported in the U.S.

Camels and bats can carry the virus. It spreads from animal to person and from person to person through the air in droplets (respiratory secretions) that you breathe in or other forms of close contact. Experts are still learning about how MERS-CoV spreads. 

What are the symptoms of MERS?

In some cases, MERS causes no symptoms. Most often, symptoms of MERS start about 5 days after being exposed to the virus. But they can develop up to 14 days later.

Common symptoms include:

• Fever

• Chills

• Coughing

• Sore throat

• Runny nose

• Trouble breathing

• Muscle aches

Less common symptoms include:

• Bloody coughing

• Nausea and vomiting

• Diarrhea

• Shortness of breath

What are possible complications from MERS?

In some cases, MERS can cause severe problems. Like many other infections, MERS is likely more severe in the very young, the very old, those with underlying illness, such as diabetes or heart failure, and those who have weak immune systems. But these links are still not clear. Complications can include:

• Lung infection (pneumonia)

• Breathing (respiratory) failure and need for a breathing machine (ventilator)

• Failure of the kidneys and other organs

• Widespread infection and low blood pressure (septic shock)

These severe complications are more likely to lead to death from MERS.

How is MERS diagnosed?

Your healthcare provider will ask about your health history. They will also ask about your recent travel and contact with sick people. The provider may also ask about recent contact with camels.

You will have tests to check for the cause of your symptoms. The symptoms of MERS are very similar to illnesses caused by other viruses, such as the flu. You may have tests such as:

• Chest X-ray. X-rays use a small amount of radiation to make images of the inside of your body. A chest X-ray is done to check for problems in your lungs.

• Blood tests. Blood is taken from a vein in your arm or hand. This is done to test for the MERS virus or other illness.

• Nasal or throat swab. A cotton-tipped swab is wiped inside your nose or throat. This is done to check for viruses in your nasal mucus.

• Sputum culture. A small sample of mucus coughed from your lungs is collected. It is checked for the virus.

How is MERS treated?

Currently no medicine has been clearly shown to treat MERS directly, but sometimes experimental medicines may be offered. Treatment for MERS consists mainly of supporting your body while it fights the disease. This is known as supportive care. Supportive care may include:

• Pain medicine. This includes acetaminophen and ibuprofen. They are used to help ease pain and reduce fever.

• Bed rest. This helps your body fight the illness.

Care during severe illness may include:

• IV (intravenous) fluids. These are given through a vein to help keep your body hydrated.

• Oxygen. Supplemental oxygen or ventilation with a breathing machine (ventilator) may be given. This is done to keep enough oxygen in your body.

• Vasopressor medicine. These help to raise blood pressure when it is too low from shock.

Are you at risk for MERS?

If you’ve been to a place where people have been sick with MERS, you are at risk for infection. You are at risk if you:

• Recently traveled in or near the Arabian Peninsula

• Had contact with a sick person who recently traveled to the Arabian Peninsula

• Had contact with camels or their milk, urine, or meat

• Had contact with a person who was diagnosed with MERS

• Had contact with a healthcare worker who has been in contact with people who have MERS

How can MERS be prevented?

It is not yet known how MERS is passed along. It may be passed from an infected person. It may be passed along by an infected camel or bat. There is currently no vaccine for MERS. Prevention is done by not having contact with the virus, and taking special care around the virus. If you are in an area with MERS:

• Wash your hands often for at least 20 seconds with soap and clean, running water. Scrub between your fingers and under your fingernails. Or use an alcohol-based hand sanitizer often. The sanitizer should contain at least 60% alcohol.

• Only touch your eyes, nose, or mouth with clean hands.

• Wash your hands as above after touching animals. Don't have contact with sick animals.

• Don't have contact with camels.

• Don’t drink raw (unpasteurized) camel milk.

• Don’t eat undercooked camel meat.

• Try to have less contact with people who are sick.

• Don’t share eating or drinking tools with sick people.

• Don’t kiss someone who is sick.

• Clean surfaces regularly with disinfectant.

What to do if you are at risk for MERS

If you have had close contact with someone who has been diagnosed with MERS:

• Call your healthcare provider. They can talk with local health staff to see what action may be needed.

• Follow all instructions from your provider. This may include having blood tests.

• Take your temperature every morning and evening for at least 14 days. This is to check for fever. Keep a record of the readings.

• Keep watch for symptoms of MERS. Tell your provider if you have symptoms.

If you have a fever or other MERS symptoms:

• Don’t panic. Keep in mind that other illnesses can cause similar symptoms.

• Stay away from work, school, and public places. Limit physical contact with family members. Don't kiss anyone or share eating or drinking utensils. Clean surfaces you touch with disinfectant. This is to help prevent the virus from spreading.

• Call your healthcare provider. Explain that you have been exposed to MERS and have symptoms. Do this before going to the hospital. Your provider may be able to see you at their clinic. Or they may send you to the emergency room.

• Keep in mind that healthcare staff may wear protective equipment such as masks, gowns, gloves, and eye protection. This is to prevent the possible virus from spreading.

• Tell the healthcare staff about recent travel. This includes local travel on public transport. Staff may need to find other people you have been in contact with.

• Follow all instructions the healthcare staff give you.

Travel precautions

The CDC and World Health Organization (WHO) don't recommend anyone change travel plans because of MERS. But be aware of travel restrictions in the area you are traveling. Practice good handwashing at all times. For more information,

• CDC MERS travel information at https://www.cdc.gov/coronavirus/mers/travel.html or WHO MERS travel

• WHO MERS travel guidance at https://www.who.int/health-topics/middle-east-respiratory-syndrome-coronavirus-mers/technical-guidance/travel-and-mass-gatherings

To learn more

To learn more about MERS, visit the CDC at www.cdc.gov/coronavirus/mers/ .