Severe acute respiratory syndrome (SARS) is a viral respiratory illness caused by a coronavirus, called SARS-associated coronavirus (SARS-CoV). SARS was first reported in Asia in February 2003. The illness spread to more than two dozen countries in North America, South America, Europe, and Asia before the SARS global outbreak of 2003 was contained.

Currently, there is no known SARS transmission anywhere in the world. The most recent human cases of SARS-CoV infection were reported in China in April 2004 in an outbreak resulting from laboratory-acquired infections. CDC and its partners, including the World Health Organization, continue to monitor the SARS situation globally.

The Disease

What is SARS?

Severe acute respiratory syndrome (SARS) is a viral respiratory illness that was recognized as a global threat in March 2003, after first appearing in Southern China in November 2002.

What are the symptoms and signs of SARS?

The illness usually begins with a high fever (measured temperature greater than 100.4°F [>38.0°C]). The fever is sometimes associated with chills or other symptoms, including headache, general feeling of discomfort, and body aches. Some people also experience mild respiratory symptoms at the outset. Diarrhea is seen in approximately 10 percent to 20 percent of patients. After 2 to 7 days, SARS patients may develop a dry, nonproductive cough that might be accompanied by or progress to a condition in which the oxygen levels in the blood are low (hypoxia). In 10 percent to 20 percent of cases, patients require mechanical ventilation. Most patients develop pneumonia.

What is the cause of SARS?

SARS is caused by a previously unrecognized coronavirus, called SARS-associated coronavirus (SARS-CoV). It is possible that other infectious agents might have a role in some cases of SARS.

How is SARS spread?

The primary way that SARS appears to spread is by close person-to-person contact. SARS-CoV is thought to be transmitted most readily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes. Droplet spread can happen when droplets from the cough or sneeze of an infected person are propelled a short distance (generally up to 3 feet) through the air and deposited on the mucous membranes of the mouth, nose, or eyes of persons who are nearby. The virus also can spread when a person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, nose, or eye(s). In addition, it is possible that SARS-CoV might be spread more broadly through the air (airborne spread) or by other ways that are not now known.

What does “close contact” mean?

Close contact is defined as having cared for or lived with a person known to have SARS or having a high likelihood of direct contact with respiratory secretions and/or body fluids of a patient known to have SARS. Examples include kissing or embracing, sharing eating or drinking utensils, close conversation (within 3 feet), physical examination, and any other direct physical contact between people. Close contact does not include activities such as walking by a person or briefly sitting across a waiting room or office.

If I were exposed to SARS-CoV, how long would it take for me to become sick?

The time between exposure to SARS-CoV and the onset of symptoms is called the “incubation period.” The incubation period for SARS is typically 2 to 7 days, although in some cases it may be as long as 10 days. In a very small proportion of cases, incubation periods of up to 14 days have been reported.

How long is a person with SARS infectious to others?

Available information suggests that persons with SARS are most likely to be contagious only when they have symptoms, such as fever or cough. Patients are most contagious during the second week of illness. However, as a precaution against spreading the disease, CDC recommends that persons with SARS limit their interactions outside the home (for example, by not going to work or to school) until 10 days after their fever has gone away and their respiratory (breathing) symptoms have gotten better.

Is a person with SARS contagious before symptoms appear?

To date, no cases of SARS have been reported among persons who were exposed to a SARS patient before the onset of the patient’s symptoms.

What medical treatment is recommended for patients with SARS?

CDC recommends that patients with SARS receive the same treatment that would be used for a patient with any serious community-acquired atypical pneumonia. SARS-CoV is being tested against various antiviral drugs to see if an effective treatment can be found.

If there is another outbreak of SARS, how can I protect myself?

If transmission of SARS-CoV recurs, there are some common-sense precautions that you can take that apply to many infectious diseases. The most important is frequent hand washing with soap and water or use of an alcohol-based hand rub. You should also avoid touching your eyes, nose, and mouth with unclean hands and encourage people around you to cover their nose and mouth with a tissue when coughing or sneezing.

Global SARS Outbreak, 2003

How many people contracted SARS worldwide during the 2003 outbreak? How many people died of SARS worldwide?

During November 2002 through July 2003, a total of 8,098 people worldwide became sick with severe acute respiratory syndrome that was accompanied by either pneumonia or respiratory distress syndrome (probable cases), according to the World Health Organization (WHO). Of these, 774 died. By late July 2003, no new cases were being reported, and WHO declared the global outbreak to be over.

How many people contracted SARS in the United States during the 2003 outbreak? How many people died of SARS in the United States?

In the United States, only eight persons were laboratory-confirmed as SARS cases. There were no SARS-related deaths in the United States. All of the eight persons with laboratory-confirmed SARS had traveled to areas where SARS-CoV transmission was occurring.

SARS Situation, 2004

Updated Apr 26, 2004

What is the current SARS situation in the world?

In April 2004, the Chinese Ministry of Health reported several new cases of possible SARS in Beijing and in Anhui Province, which is located in east-central China. As of April 26, the Ministry of Health had reported eight possible SARS cases: six in Bejing and two in Anhui Province. One of the patients in Anhui Province died. Nearly 1000 contacts of these patients with possible SARS are under medical observation, including 640 in Beijing and 353 in Anhui.

In addition, health authorities have reported that two doctors who treated one of one of the patients during her hospitalization in Anhui have developed fever. A person in close contact with one of the doctors has also developed fever.

To date, all diagnosed cases and cases under investigation have been linked to chains of transmission involving close personal contact with an identified case. There is no evidence of wider transmission in the community. Additional information on the SARS situation in Chinaexternal icon.

CDC is monitoring this evolving situation in China and will provide additional information on this website as it becomes available.

At this time, CDC is not advising changes in the current U.S. SARS control measures other than the recommendations stated in the HAN Information Update for April 23. This update contains additional details about the reported SARS cases. For updates on the current situation regarding SARS, refer to other pages on CDC’s SARS website. Travel information is provided on CDC’s Travelers’ Health website.

SARS-Associated Coronavirus

What are coronaviruses?

Coronaviruses are a group of viruses that have a halo or crown-like (corona) appearance when viewed under a microscope. These viruses are a common cause of mild to moderate upper-respiratory illness in humans and are associated with respiratory, gastrointestinal, liver and neurologic disease in animals.

If coronaviruses usually cause mild illness in humans, how could this new coronavirus be responsible for a potentially life-threatening disease such as SARS?

There is not enough information about the new virus to determine the full range of illness that it might cause. Coronaviruses have occasionally been linked to pneumonia in humans, especially people with weakened immune systems. The viruses also can cause severe disease in animals, including cats, dogs, pigs, mice, and birds.

How long can SARS-CoV survive in the environment?

Preliminary studies in some research laboratories suggest that the virus may survive in the environment for several days. The length of time that the virus survives likely depends on a number of factors. These factors could include the type of material or body fluid containing the virus and various environmental conditions such as temperature or humidity. Researchers at CDC and other institutions are designing standardized experiments to measure how long SARS-CoV can survive in situations that simulate natural environmental conditions.

Laboratory Testing

Is there a laboratory test for SARS?

Yes, several laboratory tests can be used to detect SARS-CoV. A reverse transcription polymerase chain reaction (RT-PCR) test can detect SARS-CoV in clinical specimens such as blood, stool, and nasal secretions. Serologic testing also can be performed to detect SARS-CoV antibodies produced after infection. Finally, viral culture has been used to detect SARS-CoV.

What is a PCR test?

PCR (or polymerase chain reaction) is a laboratory method for detecting the genetic material of an infectious disease agent in specimens from patients. This type of testing has become an essential tool for detecting infectious disease agents.

What does serologic testing involve?

A serologic test is a laboratory method for detecting the presence and/or level of antibodies to an infectious agent in serum from a person. Antibodies are substances made by the body’s immune system to fight a specific infection.

What does viral culture and isolation involve?

For a viral culture, a small sample of tissue or fluid that may be infected is placed in a container along with cells in which the virus can grow. If the virus grows in the culture, it will cause changes in the cells that can be seen under a microscope.

Severe Acute Respiratory Syndrome (SARS) is a respiratory illness that affected many people worldwide in 2003. It was caused by a coronavirus, called SARS-associated coronavirus (SARS-CoV). SARS was first reported in Asia in February 2003. The illness spread to 29 countries, where 8,096 people got SARS and 774 of them died. The SARS global outbreak was contained in July 2003. Since 2004, there have not been any known cases of SARS reported anywhere in the world.

Key Facts

• SARS was caused by a new coronavirus that had never been found in people before.
• In 2003, a total of 8,096 people in 29 countries got SARS and 774 of them died.
• Only eight people in the United States got SARS. None of them died.
• Health professionals around the world worked together to successfully contain the outbreak in 2003.
• In six months, the global SARS outbreak cost the world an estimated $40 billion.

A Virus that Wears a Crown

SARS is caused by a virus called SARS-associated coronavirus (SARS-CoV). Under a microscope you can see that each virus particle is surrounded by a corona, or crown. These crowns are little proteins that live on the surface of the virus to determine which cells it can infect. SARS-CoV comes from the same family of viruses that cause the common cold.

SARS Symptoms

A high fever was typically the first sign of illness for people who got SARS. Other symptoms included headaches, malaise (feeling of discomfort), body aches, cough, and diarrhea. Most people developed pneumonia and needed to be hospitalized. Some needed a breathing machine.

How SARS Was Spread

Infected people spread SARS-CoV by coughing, sneezing, and having close contact with others. When infected people touched surfaces, others got infected by touching these things, then putting their fingers in their eyes, nose, or mouth. Doctors had to wear respirators and sometimes full body protection to keep from getting infected.

Solving the Outbreak

A CDC laboratory scientist in 2003 processes blood samples to be tested for SARS. Using special tests to detect antibodies—proteins the body’s immune system produces to fight viruses like one that caused SARS, scientists were able to accurately identify SARS patients. CDC’s lab scientists developed and sent these tests to labs across the nation.

Prevention Tips

• Wash your hands often with soap and water for 20 seconds, and help young children do the same.
• 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 close contact, such as kissing, or sharing cups or eating utensils, with sick people.
• Clean and disinfect frequently touched surfaces, such as toys and doorknobs.

In general, SARS begins with a high fever (temperature greater than 100.4°F [>38.0°C]). Other symptoms may include headache, an overall feeling of discomfort, and body aches. Some people also have mild respiratory symptoms at the outset. About 10 percent to 20 percent of patients have diarrhea. After 2 to 7 days, SARS patients may develop a dry cough. Most patients develop pneumonia.

The main way that SARS seems to spread is by close person-to-person contact. The virus that causes SARS is thought to be transmitted most readily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes. Droplet spread can happen when droplets from the cough or sneeze of an infected person are propelled a short distance (generally up to 3 feet) through the air and deposited on the mucous membranes of the mouth, nose, or eyes of persons who are nearby. The virus also can spread when a person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, nose, or eye(s). In addition, it is possible that the SARS virus might spread more broadly through the air (airborne spread) or by other ways that are not now known.

Severe acute respiratory syndrome (SARS) is a viral respiratory illness caused by a coronavirus, called SARS-associated coronavirus (SARS-CoV). SARS was recognized as a global threat in March 2003, after first appearing in Southern China in November 2002. Over the next few months, the illness spread to more than two dozen countries in North America, South America, Europe, and Asia. Although the 2003 global outbreak was contained, it is possible that person-to-person transmission of SARS-CoV might recur. This fact sheet gives information about the illness and important instructions for preventing the spread of SARS.

Symptoms of SARS

The illness usually begins with a fever (measured temperature greater than 100.4°F [>38.0°C]). The fever is sometimes associated with chills or other symptoms, including headache, general feeling of discomfort, and body aches. Some people also have mild respiratory symptoms at the outset. About 10 percent to 20 percent of patients have diarrhea. After 2 to 7 days, SARS patients may develop a dry, nonproductive cough or feel short of breath. These symptoms might be accompanied by or progress to a ondition in which the oxygen levels in the blood are low (hypoxia). Most patients develop pneumonia.

How SARS spreads

The main way that SARS appears to spread is by close person-to-person contact. The virus that causes SARS is thought to be transmitted most readily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes. Droplet spread can happen when droplets from the cough or sneeze of an infected person are propelled a short distance (generally up to 3 feet) through the air and deposited on the mucous membranes of the mouth, nose, or eyes of persons who are nearby. The virus also can spread when a person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, nose, or eye(s). In addition, it is possible that SARS-CoV might be spread more broadly through the air (airborne spread) or by other ways that are not now known.

What does “close contact” mean?

In the context of SARS, close contact means having cared for or lived with someone with SARS or having a high likelihood of direct contact with the respiratory secretions and/or body fluids of a patient known to have SARS. Examples include kissing or embracing, sharing eating or drinking utensils, talking to someone within 3 feet, physical examination, and any other direct physical contact between people. Close contact does not include activities such as walking by a person or briefly sitting across a waiting room or office.

Steps to protect yourself and the people around you

If you have SARS, or you have close contact with someone who does, follow these instructions:

If you think you (or someone in your family) might have SARS, you should:

• Call your healthcare provider as soon as possible. Call ahead and alert the healthcare provider before your visit so that precautions can be taken to keep from exposing other people .
• Cover your mouth and nose with a tissue when coughing or sneezing.
• Be careful not to expose others. If you have been exposed to SARS and become ill with any symptoms, limit your activities outside the home. Avoid public transportation (e.g., bus, taxi). Do not go to work, school, out-of-home child care, church, or activities in other public areas until after you are told that you do not have SARS.
• Follow any other instructions provided by local health authorities.

If you have SARS and are being cared for at home, you should:

• Follow the instructions given by your healthcare provider.
• Limit your activities outside the home except as necessary for medical care. For example, do not go to work, school, or public areas. If you must leave the home, wear a mask, if tolerated. Do not use public transportation.
• Wash your hands often and well, especially after you blow your nose.
• Cover your mouth and nose with a tissue when you sneeze or cough.
• If possible, wear a surgical mask when around other people in your home. If you can’t wear a mask, the members of your household should wear one when they are around you.
• Don’t share silverware, towels, or bedding with anyone in your home until these items have been washed with soap and hot water.
• Be sure that surfaces (counters, tabletops, door knobs, bathroom fixtures, etc.) that have been contaminated by your body fluids (sweat, saliva, mucous, or even vomit or urine) are cleaned with a household disinfectant used according to the manufacturer’s instructions. Be sure that the person who cleans the surfaces wears disposable gloves during all cleaning activities. Disposable gloves should be thrown out after use and should not be reused.
• Follow these instructions for 10 days after your fever and respiratory symptoms have gone away or until the health department says you can return to normal activities.

If you are caring for someone at home who has SARS, you should:

• Be sure that you understand and can help the SARS patient follow the healthcare provider’s instructions for medication and care.
• Be sure that all members of your household are washing their hands frequently with soap and hot water or using an alcohol-based hand rub.
• Wear disposable gloves if you will have direct contact with body fluids of a SARS patient. However, wearing gloves is not a substitute for good hand hygiene. After contact with body fluids of a SARS patient, remove the gloves, throw them out, and wash your hands. Do not wash or reuse the gloves.
• Encourage the person with SARS to cover his or her mouth and nose with a tissue when coughing or sneezing. If possible, the person with SARS should wear a surgical mask during close contact with other people in the home. If the person with SARS cannot wear a surgical mask, other members of the household should wear one when in the room with that person.
• Do not use silverware, towels, bedding, clothing, or other items that have been used by the person with SARS until these items have been washed with soap and hot water.
• Clean surfaces in the patient’s room and the bathroom fixtures used by the patient daily, with a household disinfectant used according to the manufacturer’s instructions. When cleaning, wear disposable gloves, and dispose of them after use. Or, use household utility gloves.
• Limit the number of persons in the household to those who are essential for patient support. Other household members should either be relocated or minimize contact with the patient in the home. This is particularly important for persons at risk of serious complications of SARS (e.g., persons with underlying heart or lung disease, diabetes mellitus, older age).
• Unexposed persons who do not have an essential need to be in the home should not visit.
• Follow these instructions for 10 days after the sick person’s fever and respiratory symptoms have gone away or until the health department says the SARS patient can return to normal activities.
• For 10 days after your last exposure to the person with SARS, be vigilant for fever (i.e., measure your temperature twice daily), respiratory symptoms, and other early symptoms of SARS. Common early symptoms include chills, body aches, and headache. In some patients, body aches and headache may appear 12 to 24 hours before fever. Diarrhea, sore throat, and runny nose may also be early symptoms of SARS. If you do not have any of these symptoms, you do not need to limit your activities outside the home. You may go to work, school, out-of-home child care, church, or activities in other public areas.
• Follow any other instructions provided by local health authorities.
• If you start feeling sick, especially if you develop a fever, respiratory symptoms, or other early symptoms of SARS, contact your healthcare provider immediately, and tell the healthcare provider that you have had close contact with a SARS patient.

Steps to protect yourself and the people around you

If you have SARS, or you have close contact with someone who does, follow these instructions:

If you think you (or someone in your family) might have SARS, you should:

• Call your healthcare provider as soon as possible. Call ahead and alert the healthcare provider before your visit so that precautions can be taken to keep from exposing other people .
• Cover your mouth and nose with a tissue when coughing or sneezing.
• Be careful not to expose others. If you have been exposed to SARS and become ill with any symptoms, limit your activities outside the home. Avoid public transportation (e.g., bus, taxi). Do not go to work, school, out-of-home child care, church, or activities in other public areas until after you are told that you do not have SARS.
• Follow any other instructions provided by local health authorities.

If you have SARS and are being cared for at home, you should:

• Follow the instructions given by your healthcare provider.
• Limit your activities outside the home except as necessary for medical care. For example, do not go to work, school, or public areas. If you must leave the home, wear a mask, if tolerated. Do not use public transportation.
• Wash your hands often and well, especially after you blow your nose.
• Cover your mouth and nose with a tissue when you sneeze or cough.
• If possible, wear a surgical mask when around other people in your home. If you can't wear a mask, the members of your household should wear one when they are around you.
• Don't share silverware, towels, or bedding with anyone in your home until these items have been washed with soap and hot water.
• Be sure that surfaces (counters, tabletops, door knobs, bathroom fixtures, etc.) that have been contaminated by your body fluids (sweat, saliva, mucous, or even vomit or urine) are cleaned with a household disinfectant used according to the manufacturer's instructions. Be sure that the person who cleans the surfaces wears disposable gloves during all cleaning activities. Disposable gloves should be thrown out after use and should not be reused.
• Follow these instructions for 10 days after your fever and respiratory symptoms have gone away or until the health department says you can return to normal activities.

If you are caring for someone at home who has SARS, you should:

• Be sure that you understand and can help the SARS patient follow the healthcare provider's instructions for medication and care.
• Be sure that all members of your household are washing their hands frequently with soap and hot water or using an alcohol-based hand rub.
• Wear disposable gloves if you will have direct contact with body fluids of a SARS patient. However, wearing gloves is not a substitute for good hand hygiene. After contact with body fluids of a SARS patient, remove the gloves, throw them out, and wash your hands. Do not wash or reuse the gloves.
• Encourage the person with SARS to cover his or her mouth and nose with a tissue when coughing or sneezing. If possible, the person with SARS should wear a surgical mask during close contact with other people in the home. If the person with SARS cannot wear a surgical mask, other members of the household should wear one when in the room with that person.
• Do not use silverware, towels, bedding, clothing, or other items that have been used by the person with SARS until these items have been washed with soap and hot water.
• Clean surfaces in the patient's room and the bathroom fixtures used by the patient daily, with a household disinfectant used according to the manufacturer's instructions. When cleaning, wear disposable gloves, and dispose of them after use. Or, use household utility gloves.
• Limit the number of persons in the household to those who are essential for patient support. Other household members should either be relocated or minimize contact with the patient in the home. This is particularly important for persons at risk of serious complications of SARS (e.g., persons with underlying heart or lung disease, diabetes mellitus, older age).
• Unexposed persons who do not have an essential need to be in the home should not visit.
• Follow these instructions for 10 days after the sick person's fever and respiratory symptoms have gone away or until the health department says the SARS patient can return to normal activities.
• For 10 days after your last exposure to the person with SARS, be vigilant for fever (i.e., measure your temperature twice daily), respiratory symptoms, and other early symptoms of SARS. Common early symptoms include chills, body aches, and headache. In some patients, body aches and headache may appear 12 to 24 hours before fever. Diarrhea, sore throat, and runny nose may also be early symptoms of SARS. If you do not have any of these symptoms, you do not need to limit your activities outside the home. You may go to work, school, out-of-home child care, church, or activities in other public areas.
• Follow any other instructions provided by local health authorities.
• If you start feeling sick, especially if you develop a fever, respiratory symptoms, or other early symptoms of SARS, contact your healthcare provider immediately, and tell the healthcare provider that you have had close contact with a SARS patient.