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
PREVENTION AND CONTROL: CDC
SARS is a respiratory illness that has recently been
reported in Asia, North America, and Europe. For additional information,
check the World Health Organizations (WHO) SARS Web site or visit other
pages on CDCs SARS Web
are the symptoms and signs of Severe Acute Respiratory Syndrome
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
were exposed to SARS, how long would it take for me to become
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,
medical treatment is recommended for patients with SARS?
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
Spread of SARS
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.
is the difference between droplet and airborne transmission of
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
transmission means the that the virus is spread by very small
respiratory aerosol 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
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
long is a person with SARS infectious to others?
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.
is most at risk of contracting SARS?
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 healthcare 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.
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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.
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.
evidence is there to suggest that coronaviruses may be linked with
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.
coronaviruses usually cause mild illness in humans, how could this new
coronavirus be responsible for a potentially life-threatening disease such
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.
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.
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.
about reports suggesting that the cause of SARS may be human
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
is human metapneumovirus?
Human metapneumovirus is a recently
recognized virus that appears to be responsible for some of the
respiratory infections that occur in adults and children during the winter
months. It is related to the viruses that cause a broad range of
respiratory and childhood illnesses, including mumps, measles, and croup.
about reports from other laboratories suggesting that the cause of SARS
may be a paramyxovirus?
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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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.
many people have died from SARS?
Visit WHO's SARS page
for a daily update of SARS cases and deaths.
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:
more than 160 infectious disease experts and support staff to work on
the SARS response.
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 healthcare facilities, in the household, when traveling, and in
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
CDC is committed to communicating regularly and effectively with public
health professionals, elected leaders, clinicians, and the general
Travel and Quarantine
are CDC's quarantine officials doing to prevent and control the spread of
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.
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
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.
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.
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
healthcare 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
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
actually notifies quarantine officials of potential SARS cases? Is it the
crew of the airplane or ship? The passengers?
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.
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.
does a quarantine official do if a passenger is identified as meeting the
case definition for suspected SARS?
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.
does a quarantine official do if a passenger identified as meeting the
case definition for suspected SARS refuses to be
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.
there any reason to think SARS is or is not related to
available about SARS indicates that people who appear to be most at risk
are either healthcare 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.
Personal and Household
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 healthcare provider.
To help the healthcare 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.
has CDC recommended to prevent transmission of SARS in households?
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:
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
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.
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
- 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.
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.
household cleaners are sufficient for disinfecting toilets, sinks, and
other surfaces touched by patients with SARS, but the cleaners must be
members of the household need not restrict their outside activities
unless they develop symptoms of SARS, such as a fever or respiratory
has CDC recommended to prevent transmission of SARS in the health care
Transmission of SARS to healthcare 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 healthcare settings as well as
for the management of
exposures to SARS in healthcare and other institutional
precautions should healthcare 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. Healthcare 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. Healthcare 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
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.
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
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 healthcare provider. To help your healthcare 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
has recommended guidelines for medical aircraft that transport SARS
patients. Should commercial airlines also follow these guidelines?
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.