Severe Acute Respiratory Syndrome (SARS)
Primary reference(s)
WHO, 2019. Preliminary Clinical Description of Severe Acute Respiratory Syndrome. World Health Organization (WHO). Accessed 16 December 2019.
Additional scientific description
Severe acute respiratory syndrome (SARS) was first identified at the end of February 2003 during an outbreak that emerged in China and spread to four other countries (WHO, 2020). The World Health Organization (WHO) coordinated the international investigation and worked closely with health authorities in affected countries to provide epidemiological, clinical and logistical support and to bring the outbreak under control (WHO, 2019).
Most patients identified with SARS were previously healthy adults aged 25 to 70 years. A few suspected cases of SARS have been reported among children under 15 years of age (WHO, 2020).
SARS is spread is by close person-to-person contact. The virus that causes SARS is thought to be transmitted most readily by respiratory droplets (droplet spread) produced when an infected person coughs or sneezes. The virus can also spread when a person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, nose, or eye(s). In addition, it is possible that the SARS virus might spread more broadly through the air (airborne spread) or by other ways that are not now known. The incubation period of SARS is usually 2 to 7 days but may be as long as 10 days (WHO, 2020).
SARS usually begins with a prodrome of fever (>38°C), which is often high, sometimes associated with chills and rigors and sometimes accompanied by other symptoms including headache, malaise, and myalgias. At the onset of illness, some cases have mild respiratory symptoms (WHO, 2020).
The lower respiratory phase begins after 3 to 4 days with the onset of a dry, non-productive cough or dyspnea that may be accompanied by or progress to hypoxemia. In 10% to 20% of cases, the respiratory illness is severe enough to require intubation and mechanical ventilation (WHO, 2020). There is no cure or vaccine for SARS and treatment should be supportive and based on the patient’s symptoms (WHO, 2020).
The case fatality among persons with illness meeting the current WHO case definition for probable and suspected cases of SARS is around 3% (WHO, 2020).
Laboratory diagnosis is key to determine the aetiology of the symptoms including differential diagnosis with other coronaviruses including SARS-CoV-2. Early clinical recognition of SARS-CoV disease still relies on a combination of clinical, laboratory and epidemiologic features. No specific clinical findings can distinguish with certainty SARS-CoV disease from other respiratory illnesses rapidly (CDC, 2004).
No vaccine or specific treatment is available for SARS but it is part of the priority list for the WHO Research and Development Blueprint for Action to Prevent Epidemics (WHO, 2016a).
The WHO has published guidance on case classification and surveillance standards (WHO, 2003a). Metrics and numeric limits Not applicable.
Metrics and numeric limits
Not applicable.
Key relevant UN convention / multilateral treaty
International Health Regulations (2005), 3rd ed. (WHO, 2016b).
Examples of drivers, outcomes and risk management
Prevention mainly is through infection control in healthcare, home and community settings (WHO, 2019). Personal preventive measures to prevent spread of the virus include frequent hand washing using soap or alcohol-based disinfectants. For those with a high risk of contracting the disease, such as healthcare workers, use of personal protective equipment, including a mask, goggles and an apron is mandatory. Whenever possible, household contacts should also wear a mask (WHO, 2020).
Control of SARS relies on the rapid identification of cases and their appropriate management, including the isolation of suspect and probable cases and the management of their close contacts (WHO, 2019). Individuals under investigation should be placed in respiratory isolation and precautions strictly followed (WHO, 2019).
To further reduce the risk that travellers may carry the SARS virus to new areas, international travellers departing from areas with local transmission should be screened for possible SARS at the point of departure (WHO, 2003b).
Controlling outbreaks relies on containment measures including: prompt detection of cases through good surveillance networks and including an early warning system; isolation of suspected or probable cases; tracing to identify both the source of the infection and contacts of those who are sick and may be at risk of contracting the virus; quarantine of suspected contacts for 10 days; exit screening for outgoing passengers from areas with recent local transmission by asking questions and temperature measurement; and disinfection of aircraft and cruise vessels having SARS cases on board using WHO guidelines (WHO, 2020).
References
CDC, 2004. Clinical Guidance on the Identification and Evaluation of Possible SARS-CoV Disease among Persons Presenting with Community-Acquired Illness. Accessed 9 April 2021.
WHO, 2003a. Case Definitions for Surveillance of Severe Acute Respiratory Syndrome (SARS). World Health Organization (WHO). Accessed 16 December 2019.
WHO, 2003b. SARS: Summary of WHO measures related to international travel. World Health Organization (WHO). Accessed 16 December 2019.
WHO, 2016a. An R &D blueprint for action to prevent epidemics. World Health Organization (WHO). Accessed 25 September 2020.
WHO, 2016b. International Health Regulations (2005), 3rd ed. World Health Organization (WHO). Accessed 26 September 2020.
WHO, 2019. Preliminary Clinical Description of Severe Acute Respiratory Syndrome. World Health Organization (WHO). Accessed 16 December 2019.
WHO, 2020. Severe Acute Respiratory Syndrome (SARS). World Health Organization (WHO). Accessed 2 November 2020.