Condition 101 About Severe Acute Respiratory Syndrome

What is the definition of Severe Acute Respiratory Syndrome?

Severe acute respiratory syndrome (SARS) is a serious form of pneumonia. Infection with the SARS virus causes acute respiratory distress (severe breathing difficulty), and sometimes death.

This article is about the outbreak of SARS that occurred in 2003. For information about the 2019 coronavirus outbreak, please see the Center for Disease Control and Prevention (CDC).

What are the alternative names for Severe Acute Respiratory Syndrome?

SARS; Respiratory failure - SARS; SARS coronavirus; SARS-CoV

What are the causes for Severe Acute Respiratory Syndrome?

SARS is caused by the SARS-associated coronavirus (SARS-CoV). It is one of the coronavirus family of viruses (the same family that can cause the common cold). An epidemic of SARS started in 2003 when the virus spread from small mammals to people in China. This outbreak quickly reached global proportions, but was contained in 2003. No new cases of SARS have been reported since 2004.

When someone with SARS coughs or sneezes, infected droplets spray into the air. You can catch the SARS virus if you breathe in or touch these particles. The SARS virus may live on hands, tissues, and other surfaces for up to several hours in these droplets. The virus may be able to live for months or years when the temperature is below freezing.

While the spread of droplets through close contact caused most of the early SARS cases, SARS might also spread by hands and other objects the droplets has touched. Airborne transmission is a real possibility in some cases. Live virus has even been found in the stool of people with SARS, where it has been shown to live for up to 4 days.

With other coronaviruses, becoming infected and then getting sick again (reinfection) is common. This may also be the case with SARS.

Symptoms usually occur about 2 to 10 days after coming in contact with the virus. In some cases, SARS started sooner or later after first contact. People with active symptoms of illness are contagious. But it is not known for how long a person may be contagious after symptoms appear.

What are the symptoms for Severe Acute Respiratory Syndrome?

The main symptoms are:

  • Cough
  • Difficulty breathing
  • Fever of 100.4°F (38.0°C) or higher
  • Other breathing symptoms

The most common symptoms are:

  • Chills and shaking
  • Cough, usually starts 2 to 7 days after other symptoms
  • Headache
  • Muscle aches
  • Tiredness

Less common symptoms include:

  • Cough that produces phlegm (sputum)
  • Diarrhea
  • Dizziness
  • Nausea and vomiting

In some people, the lung symptoms get worse during the second week of illness, even after the fever has stopped.

What are the current treatments for Severe Acute Respiratory Syndrome?

People who are thought to have SARS should be checked right away by a provider. If they are suspected of having SARS, they should be kept isolated in a hospital.

Treatment may include:

  • Antibiotics to treat bacteria that cause pneumonia (until bacterial pneumonia is ruled out or if there is bacterial pneumonia in addition to SARS)
  • Antiviral medicines (although how well they work for SARS is unknown)
  • High doses of steroids to reduce swelling in the lungs (it is not known how well they work)
  • Oxygen, breathing support (mechanical ventilation), or chest therapy

In some serious cases, the liquid part of blood from people who have already recovered from SARS has been given as a treatment.

There is no strong evidence that these treatments work well. There is evidence that the antiviral medicine, ribavirin, does not work.

What is the outlook (prognosis) for Severe Acute Respiratory Syndrome?

In the 2003 outbreak, the death rate from SARS was 9% to 12% of those diagnosed. In people over age 65, the death rate was higher than 50%. The illness was milder in younger people.

In the older population, many more people became sick enough to need breathing assistance. And even more people had to go to hospital intensive care units.

Public health policies have been effective at controlling outbreaks. Many nations have stopped the epidemic in their own countries. All countries must continue to be careful to keep this disease under control. Viruses in the coronavirus family are known for their ability to change (mutate) in order to spread among humans.

What are the possible complications for Severe Acute Respiratory Syndrome?

Complications may include:

  • Respiratory failure
  • Liver failure
  • Heart failure
  • Kidney problems

When should I contact a medical professional for Severe Acute Respiratory Syndrome?

Call your provider if you or someone you have been in close contact with has SARS.

How do I prevent Severe Acute Respiratory Syndrome?

Currently, there is no known SARS transmission anywhere in the world. If a SARS outbreak occurs, reducing your contact with people who have SARS lowers your risk for the disease. Avoid travel to places where there is an uncontrolled SARS outbreak. When possible, avoid direct contact with people who have SARS until at least 10 days after their fever and other symptoms are gone.

  • Hand hygiene is the most important part of SARS prevention. Wash your hands or clean them with an alcohol-based instant hand sanitizer.
  • Cover your mouth and nose when you sneeze or cough. Droplets that are released when a person sneezes or coughs are infectious.
  • DO NOT share food, drink, or utensils.
  • Clean commonly touched surfaces with an EPA-approved disinfectant.

Masks and goggles may be useful for preventing the spread of the disease. You may use gloves when handling items that may have touched infected droplets.



Centers for Disease Control and Prevention website. Severe acute respiratory syndrome (SARS). Updated December 6, 2017. Accessed March 16, 2020.

Gerber SI, Watson JT. Coronaviruses. In: Goldman L, Schafer AI, eds. Goldman-Cecil Medicine. 26th ed. Philadelphia, PA: Elsevier; 2020:chap 342.

Perlman S, McIntosh K. Coronaviruses, including severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 155.

Top Global Doctors For Severe Acute Respiratory Syndrome

Shibo X. Jiang
Shanghai, CN
Jasper F. Chan
Lika, CN
Jaffar A. Tawfiq-Al
Alimuddin I. Zumla
Danilo Buonsenso
Rome, IT

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Clinical Trials For Severe Acute Respiratory Syndrome

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  • Phase: Phase 2/Phase 3
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  • Participants: 80
  • Start Date: July 2021
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  • Phase: Phase 1/Phase 2
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  • Participants: 200
  • Start Date: June 13, 2021
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