Key facts

• SARS is a viral respiratory illness caused by the SARS-associated coronavirus
• The illness was first reported in late February 2003 in China
• The 2003 global outbreak spread to 29 countries, resulting in 8,096 cases and 774 deaths.
• It is a respiratory virus that can spread through the air and via contaminated surfaces
• There have been no reported cases of the disease since 2004

Overview

Severe Acute Respiratory Syndrome (SARS) is a viral respiratory disease caused by a SARS-associated coronavirus. Most people who contracted it were previously healthy people between the ages of 25 and around 70. The first cases were in China in November 2002 before the disease spread around the world.

The SARS outbreak was the first severe and readily transmissible new disease of the 21st century and demonstrated the world’s interconnectedness by travelling on international travel routes. The global outbreak was contained by July 2003.

Signs and symptoms

The incubation period for SARS was typically two to seven days, but could be as long as 10 days. The first symptom was generally a fever.

Other symptoms included:

• Headache
• Malaise
• Muscle pain
• Mild respiratory symptoms
• Some patients reported diarrhoea during the early stages.

After three to seven days, a lower respiratory phase began with the onset of a dry, non-productive cough or shortness of breath.

Dangers and complications

In 10 to 20 per cent of cases, the respiratory illness was severe enough to require intubation and mechanical ventilation. The case fatality rate among people with a confirmed case of the disease was estimated to be around 9.6 per cent.

Transmission

SARS is an airborne virus that spreads through small droplets of saliva, similar to how the common cold and influenza spread. It can also spread indirectly via surfaces touched by someone infected with the virus. An investigation by the World Health Organization showed that it may also have spread via inadequate plumbing systems in apartment buildings. Virus droplets may have entered apartments via strong extractor fans.

Treatment

There is no cure or vaccine for SARS. Antivirals were not shown to be effective during the outbreak and treatment was supportive and based on the patient’s symptoms, for example the administration of oxygen and intravenous fluids.

Prevention

Controlling outbreaks relies on containment measures, including:

• Rapid detection of cases through good surveillance networks and early warning systems.
• Isolation of suspected or probable cases.
• Tracing to identify the source of infection and contacts of those who are sick.
• Quarantine of suspected contacts for 10 days.
• Exit screening for outgoing passengers from areas with recent local transmission.
• Disinfection of aircraft and cruise vessels using WHO guidelines.

Personal preventive measures include frequent hand washing with soap or alcohol-based disinfectants. Those with a high risk of contracting the disease, such as health care workers, should use personal protective equipment, including a mask, goggles, and an apron. Household contacts should also wear a mask whenever possible.

History

The first cases of what would become known as SARS first emerged in the wet markets of Guangdong in 2002 when it is thought to have spilled over to humans from civet cats. However, the World Health Organization was not alerted to this new disease until February 2003. WHO issued its first global alert in March when a patient was hospitalised in Vietnam. However, as late as April that year Chinese officials were still covering up the scale of the outbreak.

The outbreak spread to 30 countries, with Hong Kong and Canada among the hardest hit, but by July 2003 WHO said it had been mostly contained.

SARS was a harbinger of what was to come during the Covid-19 pandemic as it spread quickly via international travel routes and exposed a lack of protective equipment for health care workers. Similar containment measures such as isolation of patients, contact tracing and mask wearing were also deployed.

Useful links

who.int/severe-acute-respiratory-syndrome

nlm.nih.gov/severe-acute-respiratory-syndrome

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