Middle East Respiratory Syndrome (MERS) is an illness caused by a virus (more specifically, a coronavirus) called Middle East Respiratory Syndrome Coronavirus (MERS-CoV). MERS affects the respiratory system (lungs and breathing tubes). Most MERS patients developed severe acute respiratory illness with symptoms of fever, cough and shortness of breath. About 3-4 out of every 10 patients reported with MERS have died.
Health officials first reported the disease in Saudi Arabia in September 2012. Through retrospective investigations, health officials later identified that the first known cases of MERS occurred in Jordan in April 2012. So far, all cases of MERS have been linked to countries in and near the Arabian Peninsula.
MERS-CoV has spread from ill people to others through close contact, such as caring for or living with an infected person.
MERS can affect anyone. MERS patients have ranged in age from younger than 1 to 99 years old.
MERS-CoV, like other coronaviruses, is thought to spread from an infected person’s respiratory secretions, such as through coughing. However, the precise ways the virus spreads are not currently well understood.
Person-to-person spread of MERS-CoV, usually after close contact, such as caring for or living with an infected person, has been well documented. Infected people have spread MERS-CoV to others in healthcare settings, such as hospitals. Researchers studying MERS have not seen any ongoing spreading of MERS-CoV in the community.
All reported cases have been linked to countries in and near the Arabian Peninsula. Most infected people either lived in the Arabian Peninsula or recently traveled from the Arabian Peninsula before they became ill. A few people became infected with MERS-CoV after having close contact with an infected person who had recently traveled from the Arabian Peninsula.
Public health agencies continue to investigate clusters of cases in several countries to better understand how MERS-CoV spreads from person to person.
Currently, there is no vaccine to prevent MERS-CoV infection. The U.S. National Institutes of Health is exploring the possibility of developing one.
CDC routinely advises that people help protect themselves from respiratory illnesses by taking everyday preventive actions:
Wash your hands often with soap and water for 20 seconds, and help young children do the same. If soap and water are not available, use an alcohol-based hand sanitizer.
Cover your nose and mouth with a tissue when you cough or sneeze, then throw the tissue in the trash.
Avoid touching your eyes, nose and mouth with unwashed hands.
Avoid personal contact, such as kissing, or sharing cups or eating utensils, with sick people.
Clean and disinfect frequently touched surfaces and objects, such as doorknobs.
If you are caring for or living with a person confirmed to have, or being evaluated for, MERS-CoV infection, see Interim Guidance for Preventing MERS-CoV from Spreading in Homes and Communities.
Most people confirmed to have MERS-CoV infection have had severe acute respiratory illness with symptoms of:
shortness of breath
Some people also had gastrointestinal symptoms including diarrhea and nausea/vomiting. For many people with MERS, more severe complications followed, such as pneumonia and kidney failure. About 3-4 out of every 10 people reported with MERS have died. Most of the people who died had an underlying medical condition. Some infected people had mild symptoms (such as cold-like symptoms) or no symptoms at all; they recovered.
Based on what researchers know so far, people with pre-existing medical conditions (also called comorbidities) may be more likely to become infected with MERS-CoV, or have a severe case. Pre-existing conditions from reported cases for which we have information have included diabetes; cancer; and chronic lung, heart, and kidney disease. Individuals with weakened immune systems are also at higher risk for getting MERS or having a severe case.
Based on information we have to date, the incubation period for MERS (time between when a person is exposed to MERS-CoV and when they start to have symptoms) is usually about 5 or 6 days, but can range from 2-14 days.
There is no specific antiviral treatment recommended for MERS-CoV infection. Individuals with MERS can seek medical care to help relieve symptoms. For severe cases, current treatment includes care to support vital organ functions.