SARS (Severe Acute Respiratory Syndrome)
What everybody should know.
developed responses to many of the most commonly asked questions about
severe acute respiratory syndrome (SARS). The responses are listed under the
topics below and will be updated as new information becomes available.
PREVENTION AND CONTROL: CDC RECOMMENDATIONS
What is SARS?
respiratory syndrome (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 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 percent to 20 percent of cases, patients will
require mechanical ventilation. For more information, see the
If I were exposed to SARS, how long would
it take for me to become sick?
incubation period for SARS is typically 2 to 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,
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.
Is the use of ribavirin (or other antiviral
drugs) effective in the treatment of patients with SARS?
At present, the most efficacious treatment regimen, if any, is unknown. In
several locations, therapy has included antivirals such as oseltamivir or
ribavirin. Steroids also have been given orally or intravenously to patients
in combination with ribavirin and other antimicrobials. In the absence of
controlled clinical trials, however, the efficacy of these regimens remains
unknown. Early information from laboratory experiments suggests that
ribavirin does not inhibit virus growth or cell-to-cell spread of one
isolate of the new coronavirus that was tested. Additional laboratory
testing of ribavirin and other antiviral drugs is being done to see if an
effective treatment can be found.
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Spread of SARS
How is SARS spread?
The primary way that SARS appears to spread is by close person-to-person
contact. Potential ways in which SARS can be spread include touching the
skin of other people or objects that are contaminated with infectious
droplets and then touching your eye(s), nose, or mouth. This can happen when
someone who is sick with SARS coughs or sneezes droplets onto themselves,
other people, or nearby surfaces. It also is possible that SARS can be
spread more broadly through the air or by other ways that are currently not
How long is a person with SARS infectious
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?
Most of the U.S. cases of SARS have occurred among travelers returning to
the United States from other parts of the world affected by SARS. There have
been very few cases as a result of spread to close contacts such as family
members and health care workers. Currently, there is no evidence that SARS
is spreading more widely in the community in the United States.
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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. This new coronavirus is the
leading hypothesis for the cause of SARS, however, 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.
How long do
coronaviruses survive in the environment?
In general, enveloped viruses such as coronaviruses do not last a long time
in the environment. In earlier studies, a different coronavirus was shown to
survive for up to 3 hours on surfaces. At this time, it is uncertain how
long the newly discovered coronavirus associated with SARS can survive in
the environment. In one preliminary study, researchers in Hong Kong found
that both dried and liquid samples of the new coronavirus survived as long
as 24 hours in the environment. Additional studies are under way to examine
this important question.
coronaviruses be found in feces?
It is not uncommon for respiratory viruses to be found in feces for a period
of time. Some laboratories in the WHO network have reported finding the new
coronavirus in stool specimens. Research is under way in the United States
and other countries to learn more about the presence and concentration of
the virus in different body fluids, including feces. Researchers also are
evaluating if the virus can spread to others through different body fluids.
What evidence is there to suggest that
coronaviruses may be linked with SARS?
scientists isolated a virus from the tissues of two SARS patients and then
used several laboratory methods to characterize it. Examination by electron
microscopy revealed that the virus has the distinctive shape and appearance
of coronaviruses, and genetic analysis suggests that this new virus does
belong to the family of coronaviruses but differs from previously identified
family members. Tests of serum specimens from people with SARS showed that
they appeared to have been recently infected with this virus. Other tests
demonstrated that this previously unrecognized coronavirus was present in a
variety of clinical specimens (including specimens obtained by nose and
throat swab) from other SARS patients with direct or indirect links to the
outbreak. These results and other findings reported from laboratories
participating in the World Health Organization (WHO) network provide growing
evidence in support of the hypothesis that this new coronavirus is the cause
of SARS. Additional studies of the link between this coronavirus and SARS
are under way.
If coronaviruses usually cause mild illness
in humans, how could this new coronavirus be responsible for a potentially
life-threatening disease such as SARS?
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.
Has new information about coronavirus
changed the recommendations for medical treatment for patients with SARS?
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?
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 from other laboratories
suggesting that the cause of SARS may be a paramyxovirus?
Researchers from several laboratories participating in the WHO network have
reported the identification of a paramyxovirus in clinical specimens from
SARS patients. These laboratories are still investigating the possibility
that a paramyxovirus is a cause of SARS.
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What is the status of the SARS outbreak in
the United States?
In the United States, cases of SARS continue to be reported primarily among
people who traveled to affected areas; a small number of other people have
gotten sick after being in close contact with (that is, having cared for or
lived with) a SARS patient while in the United States. Currently, there is
no evidence that SARS is spreading more widely in the community in the
To minimize the risk for SARS among U.S. residents, the public health system
is taking careful and thorough precautions to stop the spread of SARS.
People who are suspected of having SARS are being isolated from others and
getting care. People arriving from affected parts of the world (who might
have been exposed to SARS) are receiving information about SARS and
instructions on what they should do if they become ill. SARS patients and
their contacts are being monitored to help prevent spread of the disease.
What is the status of the SARS outbreak
outside the United States?
Most cases of SARS have been reported from China. In addition, SARS cases
have been reported from more than 20 other countries. Measures to control
the spread of SARS continue to be used in countries worldwide so that the
outbreak can be contained. Visit
WHO's SARS page
for daily updates on case reports in the United States and other countries.
What is the difference between a “probable”
SARS case and a “suspect” SARS case?
Suspect SARS cases have fever, respiratory illness, and recent travel to an
affected area with community transmission of SARS and/or contact with a
suspect SARS patient. Probable cases meet the criteria for a suspect case
and also have evidence (e.g., chest X-ray) of pneumonia or respiratory
How many people have died from SARS?
WHO's SARS page
for a daily update of SARS cases and deaths.
What is the mortality rate for SARS?
As of April 23, 2003, a total of 251 SARS-related deaths – or 5.9% of all
cases of SARS – had been reported worldwide. Visit
WHO’s SARS page
for a daily update of SARS cases and deaths.
What is CDC doing to combat this health
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:
extensive laboratory testing of clinical specimens from SARS patients to
identify the cause of the disease.
a system for distributing health alert notices to travelers who may have
been exposed to cases of SARS.
its Emergency Operations Center to provide round-the-clock coordination
more than 300 infectious disease experts and support staff to work on the
medical officers, epidemiologists, and other specialists to assist with
on-site investigations around the world.
ongoing assistance to state and local health departments in investigating
possible cases of SARS in the United States.
multiple notices providing guidance on ways to minimize the risk for SARS
in health-care facilities, in the household, when traveling, and in other
CDC is committed to communicating regularly and effectively with public
health professionals, elected leaders, clinicians, and the general public.
Travel and Quarantine
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 to air passengers returning in airplanes either
directly or indirectly to the United States from China, Singapore, and
Vietnam. The notices inform travelers about SARS and its symptoms and asks
them 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 18,000 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.
recommended procedures 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 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 attending to a SARS patient. SARS also
has 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 SARS.
Who actually notifies quarantine officials
of potential SARS cases? Is it the crew of the airplane or ship? The
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
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
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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.
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Personal and Household
What should I do if I think I have SARS?
If you are ill with a fever greater than 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.
What has CDC recommended to prevent
transmission of SARS in households?
CDC has developed
interim infection control recommendations for patients with suspected
SARS in the household. The basic precautions outlined in this document
include the following:
- 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
- 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
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 symptomatic individuals before recommended appropriate
infection control precautions were implemented. CDC has developed interim
infection control recommendations for the management of exposures to SARS in
the health-care and other institutional settings. Visit
the exposure guidance page to read these recommendations.
Health-care facilities should be vigilant in conducting active surveillance
for fever or respiratory symptoms among care givers with unprotected
exposure to SARS patients. Health-care workers who develop fever or
respiratory symptoms during the 10 days following an unprotected exposure to
a SARS patient should not report for duty. Such workers should stay home and
report symptoms to the appropriate facility point of contact (e.g.,
infection control or occupational health) immediately. Exclusion from duty
should be continued for 10 days after the resolution of fever and
respiratory symptoms. During this period, infected workers should avoid
contact with people both in the facility and in the community.
Exclusion from duty is not recommended for an exposed health-care worker if
they do not have fever or respiratory symptoms; however, the worker should
report any unprotected exposure to SARS patients to the appropriate facility
point of contact immediately.
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.
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Travel and Quarantine
Are there any travel restrictions related
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 the People's Republic of
China (i.e., mainland China and Hong Kong); Hanoi, Vietnam; or Singapore may
wish to postpone their trip until further notice. CDC also has issued a
travel alert for Toronto, Canada, to recommend that U.S. travelers to
Toronto observe precautions to safeguard their health. For additional
information about travel advisories, check
CDC's Travelers' Health
site, which will be updated as necessary.
What is the difference between a “travel
alert” and a “travel advisory” issued by CDC?
CDC issues two types of notices to travelers depending on specific
situations: travel alerts and travel advisories. Travel alerts inform
travelers of a health concern in a particular area and provides advice about
specific precautions that should be taken. A travel advisory notifies
travelers of potentially more serious situations and advises that
non-essential travel be postponed.
What if I must travel to a country where
there is community spread of SARS? What precautions can I take?
As with all infectious illnesses, the first line of defense is careful hand
hygiene. As a general rule, it is good practice to wash hands frequently
with soap and water; if hands are not visibly soiled, alcohol-based hand
rubs may be used as an alternative.
the possibility of infection, you may wish to avoid close contact with large
numbers of people as much as possible. CDC does not recommend the routine
use of masks while in public areas. For more information, visit
website and specifically read
the Interim Guidelines about Severe Acute Respiratory Syndrome (SARS) for
Persons Traveling to SARS-Affected Areas.
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 more than 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 (available on this page) 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 at
this page. CDC also has developed
interim guidance for cleaning of commercial passenger aircraft after a
flight with a suspected SARS passenger.
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