Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

SARS: current knowledge and management

  • Comment

VOL: 99, ISSUE: 18, PAGE NO: 26

Franky Lever, MSc, RMN, is an epidemiological scientist, UK SARS Team, Health Protection Agency, Communicable Disease Surveillance Centre, London

Severe acute respiratory syndrome (SARS) first occurred in November 2002. It demonstrates human-to-human transmission and possible environmental transmission by undefined routes. The best available evidence indicates it is caused by a new coronavirus known as SARS CoV with a usual incubation period of 2-7 days (with some isolated reports of incubation up to 10 days). The new virus is unlike any other of this family of viruses, which includes the common cold. It is also distinct from known animal coronaviruses. SARS raises particular concern due to:
Severe acute respiratory syndrome (SARS) first occurred in November 2002. It demonstrates human-to-human transmission and possible environmental transmission by undefined routes. The best available evidence indicates it is caused by a new coronavirus known as SARS CoV with a usual incubation period of 2-7 days (with some isolated reports of incubation up to 10 days). The new virus is unlike any other of this family of viruses, which includes the common cold. It is also distinct from known animal coronaviruses. SARS raises particular concern due to:


  • Its potential for rapid spread by international air travel;
  • The risk of onward transmission to health workers;
  • The failure of empirical treatments to improve prognosis significantly;
  • The need for intensive therapy to assist breathing of one in 10 cases;
  • The death of one in 20 cases of SARS globally to date;
  • Uncertainties over transmission and best methods of control, diagnosis and treatment.
The World Health Organization (WHO) has coordinated an international collaboration of laboratory, clinical and epidemiological networks, which have allowed this first global outbreak to be identified and investigated rapidly. The next few months will tell us more about the illness and if a rapid and accurate test can be developed. More will also be learnt about the infectivity of the coronavirus and whether the response coordinated by WHO has contained the current outbreaks and prevented SARS from becoming a worldwide threat to health (Heymann, 2003).


Case definitions and surveillance


UK cases are defined as either high/low suspect or probable. A 'low suspect' case is a person with sudden onset of high fever (>38°C), cough or difficulty breathing, who has travelled in the 10 days before the onset of illness to an area in which the transmission of SARS was documented during that period. A 'high suspect' case additionally has a history of close contact with a probable SARS case from an affected area in the 10 days before onset of symptoms. A 'probable' case is defined as either a low or high suspect case who also has chest X-ray findings of pneumonia and no response to standard antimicrobial treatment, or respiratory distress syndrome (RDS). An alternative definition is where there is a death due to an unexplained respiratory illness with autopsy findings demonstrating the findings of RDS without identifiable cause in a person who travelled to an affected SARS area within 10 days of illness.


Clinicians and/or the consultants in communicable disease control (CCDC) report cases to the Communicable Disease Surveillance Centre (CDSC) of the Health Protection Agency. Each case is followed up by the individual's GP or CCDC to gather information on the outcome of the illness and any other diagnoses that have been made since the case was first reported. This information forms the basis of management of the public health risk from SARS in the UK.


Epidemiology


By the end of April 2003, WHO had reported 5,050 cases in 26 countries (WHO, 2003a). Cases have been concentrated in China (Guangdong province), Hong Kong, Singapore, Vietnam and Canada. In the UK there have been six probable cases identified and 120 suspect cases. There has been only one person who appears to have been infected within the UK. This occurred at a meeting with a man who was diagnosed as having SARS when he returned to Hong Kong.



Testing for SARS


Tests are limited in accuracy and timeliness. Serology on acute and convalescent (21 days after onset) samples is likely to be the most certain test of infection. The polymerase chain reaction (PCR) molecular test for SARS genetic material is useful earlier in the illness, but may not be sensitive enough to rule out coronavirus infection and a diagnosis of SARS.



Patients identified as probable or suspect SARS cases should also be tested for human influenza viruses, adenoviruses, respiratory syncytial virus, parainfluenza viruses, enteroviruses, human metapneumavirus as well as bacteria such as chlamydia, mycoplasma and legionella and the results reported to the CDSC.


Managing the care of patients with SARS


The summary (Box 1) outlines the management of cases in the community and hospitals. Many patients with suspected SARS can be treated at home as if they have influenza. They should be encouraged to tell their GP by phone or during a community visit if their symptoms are worsening. The Health Protection Agency has produced information for the public, which can be used as the basis for informing patients (Health Protection Agency, 2003b).



Infection control in the community


A surgical mask should be used where possible for symptomatic patients on the way to and from health care facilities as well as during their stay. To be very cautious, a patient at home could wear a surgical mask. Patients should cough and sneeze into paper tissues that can be disposed of directly into a toilet, or tied up in a plastic bag and placed in a bin.



Hand hygiene of patients and their close contacts is important: thorough washing before and after contact with a patient is advised and the use of alcohol hand wipes considered. Laundry should be washed at the highest temperature for the fabric. Eating utensils should not be shared but can be used by others after routine cleaning in a dishwasher or with hot water and washing up liquid.


Health professionals should wear disposable gloves for direct contact with the body fluids of a patient with SARS. Gloves and aprons should be worn when dealing with spillages of body fluids, which should be cleaned up using a chlorine-releasing agent of 10,000ppm available chlorine (for example, household bleach diluted to 1:10).


Environmental surfaces should be cleaned with general-purpose detergent and warm water. They should then be dried using disposable paper towels. If surfaces are contaminated disinfect using household bleach diluted to 1:100. Standard local procedures can be used for clinical waste disposal.


Infection control in hospital and A&E


The hospital's infection control policy for patients with respiratory infections should be strictly followed for patients who are probable or suspect SARS cases. The patients should preferably be nursed in a room with negative pressure or at least a room with toilet and hand-washing facilities. Standard procedures for decontaminating ventilators and other equipment should be sufficient.


The management of suspected and probable cases of SARS has been designed to minimise the numbers attending A&E departments, but some may still present with the illness. An assessment of fever, respiratory symptoms and recent travel should be included in the initial assessment of patients. If a patient appears to be a suspect or probable case, he or she should be put in a room or cubicle separate from other patients while awaiting further assessment and a decision on admission.


Patients awaiting admission from A&E should be nursed wearing a mask under the infection control measures described above. Health care workers should wear surgical masks when in close contact with the patient. The Health Protection Agency maintains up-to-date information on appropriate forms of protective wear.


Unit managers of health care facilities should maintain a list of staff who have attended a patient with probable SARS. If health care workers develop fever or respiratory symptoms during the 10 days following contact with a patient with SARS, they should report the illness as soon as possible to their GP or designated hospital doctor and their occupational health service. They should stay off duty for seven days after the resolution of fever and respiratory symptoms. During this period, co-workers should limit interactions with people both in the hospital and in the general community.


Relatives visiting SARS cases in hospital


Family members of patients with SARS are likely to fall into the definition of a close contact, whose follow-up is described fully on the Health Protection Agency's website. A system for screening such visitors for fever or respiratory symptoms should be in place. Hospitals should educate all visitors about the use of infection control precautions when visiting patients with SARS and their responsibility for adherence to them.



WEBSITE


  • Comment

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Links may be included in your comments but HTML is not permitted.