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Frequently Asked Questions: SARS (click here)
Severe Acute Respiratory Syndrome (SARS)
For more information, visit Center of Disease Control (click here)
- The Illness
- Spread of SARS
- Cause of SARS
- The Outbreak
- Travel and Quarantine
What is SARS?
SARS is a respiratory illness that has recently been reported in Asia, North America, and Europe. For additional information, check the World Health Organization’s (WHO) SARS Web site or visit other pages on CDC’s SARS Web site.
What are the symptoms and signs of Severe Acute Respiratory Syndrome (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 experience mild respiratory symptoms at the outset.
After 2 to 7 days, SARS patients may develop a dry, nonproductive cough that might be accompanied by or progress to the point where insufficient oxygen is getting to the blood. In 10% to 20% of cases, patients will require mechanical ventilation. For more information, see the MMWR dispatch.
If I were exposed to SARS, how long would it take for me to become sick?
The incubation period for SARS is typically 2-7 days; however, isolated reports have suggested an incubation period as long as 10 days. The illness usually begins with a fever (>100.4°F [>38.0°C]) (see signs and symptoms, above).
What medical treatment is recommended for patients with SARS?
CDC currently recommends that patients with SARS receive the same treatment that would be used for any patient with serious community-acquired atypical pneumonia of unknown cause. Several treatment regimens have been used for patients with SARS, but there is insufficient information at this time to determine if they have had a beneficial effect. Reported therapeutic regimens have included antibiotics to presumptively treat known bacterial agents of atypical pneumonia. Therapy also has included antiviral agents such as oseltamivir or ribavirin. Steroids also have been administered orally or intravenously to patients in combination with ribavirin and other antimicrobials. For more information on SARS, see "Interim Information and Recommendations for Health-Care Providers" on CDC's SARS web site.
SPREAD OF SARS
How is SARS spread?
The principal way SARS appears to be spread is through droplet transmission; namely, when someone sick with SARS coughs or sneezes droplets into the air and someone else breathes them in. It is possible that SARS can be transmitted more broadly through the air or from objects that have become contaminated.
What is the difference between droplet and airborne transmission of viruses?
Droplet transmission refers to the spread of viruses contained in relatively large respiratory droplets that people project when they cough or sneeze. Because of their large size, droplets travel only a short distance (usually 3 feet or less) before they settle. Droplet transmission can occur either directly when droplets are inhaled by another person, or indirectly when droplets land on an object or surface (such as a doorknob or telephone) that are then touched by another individual. Common-cold viruses (like rhinovirus) are typically spread by droplets.
Airborne transmission means the that the virus is spread by very small respiratory erosol particles or dust, which can be breathed in by people. Small aerosol particles can remain in the air and travel over a greater distance than larger respiratory droplets. Examples of viruses spread by the airborne route are influenza and measles viruses.
SARS be spread from touching contaminated objects or surfaces?
It is possible that SARS could be spread when a person touches a contaminated object or surface; however, how often this might happen, or if it happens at all, is not known at this time. Previously identified coronaviruses (scientists have reported that a new cororavirus may be the cause of SARS) have been shown to survive in the environment for as long as 3 hours. To reduce the overall risk for infection by touching contaminated objects and surfaces, CDC recommends that people wash their hands thoroughly and often with soap and water.
How long is a person with SARS infectious to others?
Information to date suggests that people are most likely to be infectious when they have symptoms, such as fever or cough. However, it is not known how long before or after their symptoms begin that patients with SARS might be able to transmit the disease to others.
Who is most at risk of contracting SARS?,br>
Cases of SARS continue to be reported primarily among people who have had direct close contact with an infected person, such as those sharing a household with a SARS patient and health-care workers who did not use infection control procedures while caring for a SARS patient. In the United States, there is no indication of community transmission at this time. CDC continues to monitor this situation very closely.
CAUSE OF SARS
What is the cause of SARS?
Scientists at CDC and other laboratories have detected a previously unrecognized coronavirus in patients with SARS. While the new coronavirus is still the leading hypothesis for the cause of SARS, other viruses are still under investigation as potential causes.
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. Coronaviruses can survive in the environment for as long as three hours.
What evidence is there to suggest that coronaviruses may be linked with SARS?
CDC scientists were able to isolate a virus from the tissues of two patients who had SARS and then used several laboratory methods to characterize the agent. Examination by electron microscopy revealed that the virus had the distinctive shape and appearance of coronaviruses. Tests of serum specimens from patients with SARS showed that the patients appeared to have recently been infected with this coronavirus. Other tests demonstrated that coronavirus was present in a variety of clinical specimens from patients, including nose and throat swabs. In addition, genetic analysis suggests that this new virus belongs to the family of coronaviruses but differs from previously identified coronaviruses. These laboratory results do not provide conclusive evidence that the new coronavirus is the cause of SARS. Additional specimens are being tested to learn more about this coronavirus and its link with SARS.
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 can also cause severe disease in animals, including cats, dogs, pigs, mice, and birds.
Has new information about coronavirus changed the recommendations for medical treatment for patients with SARS?
The possibility that coronavirus is the cause of SARS has not changed treatment recommendations. The new coronavirus is being tested against various antiviral drugs to see if an effective treatment can be found.
Is there a test for SARS?
No "test" is available yet for SARS; however, CDC, in collaboration with WHO and other laboratories, has developed 2 research tests that appear to be very promising in detecting antibodies to the new coronavirus. CDC is working to refine and share this testing capability as soon as possible with laboratories across the United States and internationally.
What about reports suggesting that the cause of SARS may be human metapneumovirus?
Researchers from several laboratories participating in the WHO laboratory network have reported finding evidence of human metapneumovirus in some specimens from SARS patients. CDC has detected this virus in one SARS patient. There is not enough information to determine what role, if any, human metapneumovirus might have in causing SARS.
How many cases of SARS have been reported so far?
Visit WHO's SARS page for daily updates on case reports in the United States and other countries. To date, most of the cases have been reported from China.
How many people have died from SARS?
Visit WHO's SARS page at www.cdc.gov for a daily update of SARS cases and deaths.
What is CDC doing to combat this health threat?
CDC is working closely with WHO and other partners as part of a global collaboration to address the SARS outbreak. For its part in this international effort, CDC has taken the following actions:
TRAVEL AND QUARANTINE
- Activated its Emergency Operations Center to provide round-the-clock coordination and response.
- Committed more than 160 infectious disease experts and support staff to work on the SARS response.
- Deployed medical officers, epidemiologists, and other specialists to assist with on-site investigations around the world.
- Provided ongoing assistance to state and local health departments in investigating possible cases of SARS in the United States.
- Issued multiple notices providing guidance on ways to minimize the risk for SARS in health-care facilities, in the household, when traveling, and in other settings.
- Conducted extensive laboratory testing of clinical specimens from SARS patients to identify the cause of the disease.
- Initiated a system for distributing health alert notices to travelers who may have been exposed to cases of SARS.
- As always, CDC is committed to communicating regularly and effectively with public health professionals, elected leaders, clinicians, and the general public.
What are CDC's quarantine officials doing to prevent and control the spread of SARS?
CDC's quarantine inspectors or their designees are distributing health alert cards (http://www.cdc.gov/ncidod/sars/travel_alert.htm) to air passengers returning in airplanes either directly or indirectly to the United States from China, Singapore, and Vietnam. The notices ask travelers to monitor their health for 10 days and to see a doctor if they get a fever with a cough or have difficulty breathing. CDC distributes approximately 15,000 health alert notices each day to air travelers returning from the affected regions at 23 ports of entry. Inspectors also are boarding airplanes if a traveler has been reported with symptoms matching the case definition of SARS.
The World Health Organization (WHO) has recommended procedures (http://www.who.int/csr/sars/travel/en/) for pre-departure screening of airline passengers from some countries for respiratory illnesses or other symptoms of SARS.
What information about SARS is being provided to people traveling on ships?
SARS information contained on CDC's health alert cards is being provided by the major shipping associations and the International Council of Cruise Lines to people traveling on cargo ships and cruise ships at U.S. ports. Inspectors also are boarding ships if a passenger or crew member has been reported with symptoms matching the case definition of SARS.
What does a quarantine inspector do?
Quarantine inspectors serve as important guardians of health at borders and ports of entry into the United States. They routinely respond to illness in arriving passengers and ensure that the appropriate medical action is taken.
What is considered routine health inspections of airplanes or ships versus what is happening now?
Routine health inspections consist of working with airline, cargo ship, and cruise ship companies to protect passengers and crew from certain infectious diseases. Quarantine inspectors meet arriving aircraft and ships reporting ill passengers and/or crew (as defined in the foreign quarantine regulations [pdf]) and assist them in getting appropriate medical treatment.
What is the risk to individuals who may have shared a plane or boat trip with a suspected SARS patient?
Cases of SARS continue to be reported primarily among persons who have had direct close contact with an infected person, such as those sharing a household with a SARS patient and health-care workers who did not use infection control procedures while attending to a SARS patient. SARS has also occurred among air travelers, primarily travelers to and from Hong Kong, Hanoi, Singapore, and mainland China.
CDC is requesting locating information from travelers who are on flights with people suspected of having SARS. CDC, with the help of state and local health authorities, is attempting to follow-up with these travelers for 14 days to make sure no one develops symptoms consistent with SAR.
Who actually notifies quarantine officials of potential SARS cases? Is it the crew of the airplane or ship? The passengers?
Under foreign quarantine regulations, the master of a ship or captain of an airplane coming into the United States from a foreign port is required by law to report certain illnesses among passengers. The illness must be reported to the nearest quarantine official. If possible, the crew of the airplane or ship will try to relocate the ill passenger or crew member away from others. If the passenger is only passing through a port of entry on his/her way to another destination, port health authorities may refer the passenger to a local health authority for assessment and care.
If I'm on board an airplane or ship with someone suspected of having SARS, will I be allowed to continue to my destination?
CDC does not currently recommend that the onward travel of healthy passengers be restricted in the event that a passenger or crew member suspected of having SARS is removed from the ship or airplane by port health authorities. All passengers and crew members may be advised by port health authorities to seek medical attention if they develop SARS symptoms.
What does a quarantine official do if a passenger is identified as meeting the case definition for suspected SARS?
Quarantine officials arrange for appropriate medical assistance to be available when the airplane lands or the ship docks, including medical isolation. Isolation is important not only for the sick passenger's comfort and care but also for the protection of members of the public. Isolation is recommended for travelers with suspected cases of SARS until appropriate medical treatment can be provided or until they are no longer infectious.
What does a quarantine official do if a passenger identified as meeting the case definition for suspected SARS refuses to be isolated?
Many levels of government (Federal, State, and local) have basic authority to compel isolation of sick persons to protect the public. In the event that it is necessary to compel isolation of a sick passenger, CDC will work with appropriate State and local officials to ensure that the passenger does not infect others.
Is there any reason to think SARS is or is not related to terrorism?
Information currently available about SARS indicates that people who appear to be most at risk are either health-care workers taking care of sick people or family members or household contacts of those who are infected with SARS. That pattern of transmission is what would typically be expected in a contagious respiratory or flu-like illness.
PREVENTION AND CONTROL: CDC RECOMMENDATIONS
PERSONAL AND HOUSEHOLD
What should I do if I think I have SARS?
People with symptoms of SARS (fever of more than 100.4°F [>38.0°C] that is accompanied by a cough and/or difficulty breathing) should consult a health-care provider. To help the health-care provider make a diagnosis, tell them about any recent travel to places where SARS has been reported or whether there was contact with someone who had these symptoms.
What has CDC recommended to prevent transmission of SARS in household?
CDC has developed interim infection control recommendations available at http://www.cdc.gov/ncidod/sars/ic-closecontacts.htm for patients with suspected SARS in the household. The basic precautions outlined in this document include the following:
HEALTH-CARE AND SETTINGS
- Infection control precautions should be continued for SARS patients for 10 days after respiratory symptoms and fever are gone. SARS patients should limit interactions outside the home and should not go to work, school, out-of-home day care, or other public areas during the 10-day period.
- During this 10-day period, all members of the household with a SARS patient should carefully follow recommendations for hand hygiene, such as frequent hand washing or the use of alcohol-based hand rubs.
- Each patient with SARS should cover his or her mouth and nose with a tissue before sneezing or coughing. If possible, a person recovering from SARS should wear a surgical mask during close contact with uninfected persons. If the patient is unable to wear a surgical mask, other people in the home should wear one when in close contact with the patient.
- Disposable gloves should be considered for any contact with body fluids from a SARS patient. However, immediately after activities involving contact with body fluids, gloves should be removed and discarded, and hands should be washed. Gloves should not be washed or reused, and are not intended to replace proper hand hygiene.
- SARS patients should avoid sharing eating utensils, towels, and bedding with other members of the household, although these items can be used by others after routine cleaning, such as washing or laundering with soap and hot water.
- Common household cleaners are sufficient for disinfecting toilets, sinks, and other surfaces touched by patients with SARS, but the cleaners must be used frequently.
- Other members of the household need not restrict their outside activities unless they develop symptoms of SARS, such as a fever or respiratory illness.
What has CDC recommended to prevent transmission of SARS in the health-care setting?
Transmission of SARS to health-care workers appears to have occurred after close contact with sick people before recommended infection control precautions were put into use. CDC has issued interim infection control recommendations for health-care settings as well as for the management of exposures to SARS in health-care and other institutional settings.
What precautions should health-care facilities follow regarding visits by close contacts of SARS patients?
Close contacts (e.g., family members or other members of the household) of SARS patients are at risk for infection. Health-care facilities should implement a system to screen for fever or respiratory symptoms among such contacts who visit the facility. Close contacts with fever or respiratory symptoms should not be allowed to enter the health-care facility as visitors and should be educated about this policy. Health-care facilities should educate all visitors about use of infection control precautions when visiting SARS patients and should emphasize the importance of following these precautions.
TRAVEL AND QUARANTINE
Are there any travel restrictions related to SARS?
At this time there are no travel restrictions in place that are directly related to SARS. However, a CDC travel advisory recommends that individuals who are planning nonessential or elective travel to mainland China, Hong Kong, Hanoi, Vietnam, or Singapore may wish to postpone their trip until further notice. For additional information about travel advisories, check CDC's Travelers' Health site, which will be updated as necessary.
If I must travel to an affected area, what sort of precautions should I take to protect against SARS?
CDC recommends that people planning elective or nonessential travel to mainland China, Hong Kong, Singapore, and Hanoi may wish to postpone their trips until further notice. People who cannot delay their travel to these locations should refer to these guidelines for information about precautions to protect against SARS.
What should I do if I have recently traveled to a country where cases of SARS have been reported?
You should monitor your own health for 10 days following your return. If you become ill with a fever of over 100.4°F [>38.0°C] that is accompanied by a cough or difficulty breathing or that progresses to a cough and/or difficulty breathing, you should consult a health-care provider. To help your health-care provider make a diagnosis, tell him or her about any recent travel to regions where cases of SARS have been reported and whether you were in contact with someone who had these symptoms.
CDC has recommended guidelines for medical aircraft that transport SARS patients. Should commercial airlines also follow these guidelines?
No. This guidance is intended specifically for air medical transport (AMT) service providers that use specialized aircraft to transport SARS patients. It should not be generalized to commercial passenger aircraft. These interim recommendations for AMT are based on standard infection control practices, AMT standards, and epidemiologic information from ongoing investigations of SARS, including experience from transport of 2 patients during this outbreak. Specific guidelines for airline crew and flight personnel of commercial aircrafts are available. CDC also has developed interim guidance for cleaning of commercial passenger aircraft after a flight with a suspected SARS passenger.