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Preface

Summary

1. Timeline

2. Virology

3. Transmission

4. Epidemiology

5. Prevention

6. Case Definition

7. Diagnostic Tests

8. Clinical Presentation and Diagnosis

9. SARS Treatment

10. Pediatric SARS



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5. Prevention

Bernd Sebastian Kamps, Christian Hoffmann

Introduction

SARS, in contrast to diseases like flu or rubella, is only moderately transmissible. The number of secondary SARS cases per index case, ranging in one epidemiologic study from 2.2 to 3.6, are considerably lower than those estimated for most other diseases with respiratory transmission (Lipsitch). This indicates that a combination of control measures, including shortening the time from symptom onset to isolation of patients, effective contact tracing and quarantine of exposed persons, can be effective in containing SARS. Indeed, such measures have been successful and have contributed to the prevention of major outbreaks in other countries. On the other hand, in the absence of such effective measures, SARS has the potential to spread widely (Lipsitch).

In the absence of a vaccine, the most effective way to control a new viral disease such as SARS is to break the chain of transmission from infected to healthy persons. In almost all documented cases, SARS is spread through close face-to-face contact with infected droplets when a patient sneezes or coughs (WHO, WER 20/2003).

For SARS, three activities - case detection, patient isolation and contact tracing - can reduce the number of people exposed to each infectious case and eventually break the chain of transmission (WHO, WER 20/2003):

  1. Case detection aims to identify SARS cases as soon after the onset of illness as possible.
  2. Once cases are identified, the next step is to ensure their prompt isolation in a properly equipped facility, and management according to strict infection control procedures.
  3. The third activity - the detective work - involves the identification of all close contacts of each case and assurance of their careful follow-up, including daily health checks and possible voluntary home isolation.

Together, these activities limit the daily number of contacts possible for each potentially infectious case. They also work to shorten the amount of time that lapses between the onset of illness and isolation of the patient, thus reducing the opportunities for the virus to spread to other patients (WHO WER 20/2003).

International Coordination

The World Health Organization (WHO) played a vital role in the containment of the first global outbreak of SARS.

After issuing a global alert about cases of severe atypical pneumonia following reports of cases among staff in the Hanoi and Hong Kong hospitals on March 12, the WHO received additional reports of more cases. Three days later, the WHO issued emergency travel recommendations to alert health authorities, physicians, and the traveling public to what was now perceived to be a worldwide threat to health. The alert included the first WHO emergency travel advisory to international travelers, healthcare professionals and health authorities, advising all individuals traveling to affected areas to be watchful for the development of symptoms for a period of 10 days after returning (http://www.who.int/csr/sarsarchive/2003_03_ 15/en/).

The decision was based on five different but related factors (WHO, Status of the Outbreak):

  1. The causative agent, and therefore the potential for continued spread, of this new disease were not yet known.
  2. The outbreaks appeared to pose a great risk to health workers who managed patients, and to the family members and other close contacts of patients.
  3. Many different antibiotics and antiviral therapies had been tried empirically and did not seem to have an effect.
  4. Though the numbers were initially small, a significant percentage of patients (25 of 26 hospital staff in Hanoi, and 24 of 39 hospital staff in Hong Kong) had rapidly progressed to respiratory failure, requiring intensive care and causing some deaths in previously healthy persons.
  5. The disease had moved out of its initial focus in Asia and appeared to have spread to North America and Europe.

Within less than two weeks, a collaborative network of laboratories set up by the WHO identified a novel coronavirus as the probable etiologic agent of SARS (see Chapter 2: Virology).

Early in April, travel advisories became more specific. On April 2, the WHO recommended that persons traveling to Hong Kong and the Guangdong Province of China consider postponing all but essential travel. (http://www.who.int/csr/sarsarchive/2003_04_ 02/en/). On April 23, the WHO extended its travel advice to Beijing and the Shanxi Province in China and to Toronto, Canada, http://www.who.int/csr/sarsarchive/2003_04_ 23/en/, and on May 8 to Tianjin, Inner Mongolia, and Taipei in Taiwan (WHO Update 50).

The global alert and the global effort coordinated by the WHO achieved its purpose. All countries with imported cases, with the exception of provinces in China, were able through

  1. prompt detection of cases
  2. immediate isolation, strict infection control, and
  3. vigorous contact tracing

to either prevent further transmission or to keep the number of additional cases very low. The early management of the SARS epidemic may well serve as a model for the containment of future epidemics and pandemics.

At the beginning of July, all travel restrictions were lifted (WHO Update 96).

Advice to travelers

The most important message for international travelers concerning SARS is to be aware of the main symptoms of SARS: high fever (> 38° C or 100.4° F), dry cough, shortness of breath or breathing difficulties. Persons who experience these symptoms and who have been in an area where there has been recent local transmission of SARS in the last 10 days are advised to contact a doctor (WHO WER 14/2003).

To further reduce the risk that travelers may carry the SARS virus to new areas, international travelers departing from areas with local transmission in the B or C categories (see "Areas with recent local transmission", http://www.who.int/csr/sarsareas/en/) should be screened for possible SARS at the time of departure. Such screening involves answering two or three questions and may include a temperature check. Travelers with one or more symptoms of SARS and who have a history of exposure, or who have fever, or who appear acutely ill should be assessed by a healthcare worker and may be advised to postpone their trip until they have recovered.

See also "Recommended procedures for prevention and management of probable cases of SARS on International Cruise Vessels", http://www.who.int/csr/sars/travel/vessels/en/ .

National Measures

The primary focus of SARS surveillance activities in countries without or with very few SARS cases is on the early identification and isolation of patients who have suspected SARS.

In contrast, countries which are affected by a severe SARS outbreak must immediately take a variety of sometimes unpopular measures to contain the epidemic. These measures generally include

  1. the creation of an emergency operating center
  2. the designation of one or more SARS hospitals
  3. the institution of efficient quarantine measures, possibly based on an extended case definition (see below)
  4. the rapid approval of pending legislation

In Singapore, the Tan Tock Seng Hospital, which is the second largest hospital in town (1500 beds) and site of the initial outbreak, was closed and designated to be the SARS hospital. Schools were closed and all public events postponed indefinitely (Mukherjee). Singapore used its military forces to assist in contact tracing and enforcement of home quarantine. All persons who were household, social, hospital, and occupational contacts during the 10 days before the onset of symptoms were traced to identify the source of infection. Persons identified as having had contact with a SARS patient from the onset of symptoms to the date of isolation were placed in home quarantine (WHO Update 70). Other measures included screening passengers at the airport and seaports, imposing a no-visitors rule on all public hospitals, and use of a dedicated private ambulance service to transport all possible cases to the SARS-designated hospital (WHO Update 70). Military forces were deployed to assist in contact tracing and to enforce quarantines. No visitors were allowed into any public hospital.

In Taiwan, the Department of Health efforts focused on limiting nosocomial transmission by designating dedicated SARS hospitals throughout the island. Approximately 100 "fever clinics" were also established to identify potential SARS patients and to minimize the risk of transmission in emergency departments. Patient care capacity was expanded by the construction of 1,000 additional negative pressure isolation rooms. Campsites and military facilities were identified to accommodate quarantined residents, and home quarantine was to be enforced through web-based cameras (MMWR 52; 461-6).

Legislation

On April 24, in Singapore, the Infectious Disease Act was amended with penalties for violations 1) to require persons who might have an infectious disease to go to a designated treatment center and to prohibit them from going to public places; 2) to prohibit breaking home quarantine with the possibility of electronic tagging and forced detention for violators; and 3) to permit contaminated areas to be quarantined and any suspected sources of infection to be destroyed. In addition, persons throughout the country were requested to monitor body temperature and to stay home or seek medical care if any signs or symptoms suggestive of SARS appeared (MMWR 52: 405-11).

This legislation allowed mandatory home quarantine for 10 days, which was enforced by CISCO, a Singapore Security Agency. CISCO served the quarantine order and installed an electronic picture (ePIC) camera in the home of each contact (MMWR 52: 405-11).

The penalty for violating quarantine was raised to as much as $5,800 and six months in prison.

Extended Case Definition

Prevention aims at identifying and isolating all people suspected of being infected with the SARS virus. The main criteria in the current WHO case definition for suspected SARS are fever (> 38°C) and respiratory symptoms such as cough, shortness of breath, or breathing difficulty, and a history of exposure (see Chapter below "Case Definition"). This definition might not be wide enough when facing an outbreak.

In one study, in the early stages of SARS, the main discriminating symptoms were not cough and breathing difficulty but fever, chills, malaise, myalgia, rigors, and, possibly, abdominal pain and headache also occurred (Rainer). Documented fever (> 38°C) was uncommon in the early stages, and radiological evidence of pneumonic changes often preceded the fever. The authors calculated that the WHO case definition has a sensitivity of 26% and a negative predictive value of 85%. The case definition, which was initially based on patients who were already hospitalized, might therefore define the tip of the iceberg of an epidemic, and not be sufficiently sensitive in assessing patients before admission to hospital (Rainer).

In addition, patients presenting with overt symptoms suggestive of SARS, including fever, are unlikely to be the source of an outbreak; in contrast, unidentified SARS cases have, to date, been responsible for most of the sudden outbreaks. Several factors contribute to the difficulties in recognizing cases of SARS (MMWR 52; 461-6):

  • Early symptoms are non-specific and may be associated with other more common illnesses
  • Patients with SARS who are immunocompromised or who have chronic conditions (e.g., diabetes mellitus or chronic renal insufficiency) might not have fever when acutely ill or have symptoms attributable to underlying disease, delaying the diagnosis of SARS
  • Some patients might not reveal useful contact information (e.g., exposure to an implicated healthcare facility) for fear of being stigmatized by the local community or causing their friends and families to be quarantined

These cases do not arise suspicion, are not isolated or managed according to strict procedures of infection control, have no restrictions on visitors, and are frequently transferred to other hospitals for further treatment or tests (WHO Update 83).

In order to prevent transmission from asymptomatic or mildly symptomatic and/or unrecognized patients, a "wide net" approach has been proposed by some national authorities.

Singapore changed the threshold criteria for initial isolation, picking up virtually every person with symptoms that might possibly indicate SARS for investigation and monitoring, regardless of whether the person had been in contact with a SARS patient (WHO Update 70). The "wide net" included all individuals with a low grade fever, chest radiograph abnormalities, or respiratory symptoms alone, leading to the admission to newly created "fever wards" of any patient with fever or respiratory symptoms or a chest x-ray abnormality which could not otherwise be explained. The rationale behind this approach is that a patient’s likelihood of having SARS becomes clearer after 48 hours of monitoring respiratory symptoms, temperature, white cell count (for lymphopenia) and chest x-rays (Fisher).

In one hospital in Singapore, this policy led within three weeks to the admission to isolation wards of 275 individuals who did not meet the WHO criteria. 72 individuals were later referred to the SARS hospital. No secondary infections were caused (Fisher).

Quarantine

Unfortunately, tests to identify SARS patients at the earliest stages of disease are not expected to be widely available soon. Early introduction of quarantine procedures for SARS should therefore be considered by health authorities. Isolation and quarantine procedures will be less effective as more cases accrue. Therefore, stringent measures implemented early in the course of the epidemic prevent the need for stricter measures as the epidemic spreads (Lipsitch).

During March, health officials in Singapore, Hong Kong, and Canada implemented quarantine and isolation measures to limit the spread of SARS. In Singapore, all primary contacts of these individuals were placed on home quarantine with financial penalties for violation; they were required to appear regularly before web cameras installed in their homes and to wear electronic bracelets if they failed to do so (Mukherjee).

On April 4, 2003, SARS was added to the list of quarantinable communicable diseases in the US. A presidential act provided the CDC with the legal authority to implement isolation and quarantine measures as part of transmissible disease-control measures, if necessary.

Quarantine does not always mean being confined to a hospital or military camp. If patients are not sick enough to warrant admission, the community may be best served by sending such patients home, provided patients can restrict their activities in a responsible manner until they are asymptomatic (Masur).

SARS Co-V may be transmitted in quarantine communities. There has been at least one report about SARS Co-V transmission during quarantine (WHO WER 22/2003). Putting patients with suspected or probable SARS and convalescent cases into isolation cubicles, each accommodating four to six patients (So), is therefore not the appropriate procedure to avoid infection. Don't "cohort" suspected cases! Patients diagnosed with SARS may or may not have the SARS virus, but they are at risk of contracting the infection if they are grouped with infected patients (Hon 2003b).

Reduce travel between districts

A recent analysis of the Hong Kong epidemic concluded that a complete ban on travel between districts could have the potential to reduce the transmission rate by 76% (Riley). This suggests that restrictions on longer-range population movement might represent a useful control measure in circumstances where it is not possible to substantially reduce the average onset-to-hospitalization time – for example in resource-poor countries, or if a number of super-spreading events occur in close succession and hospital capacity is temporarily exceeded (Riley).

Quarantine after Discharge

There is little reliable information about the duration of quarantine after discharge. In Singapore, all inpatients who were discharged from a hospital with previous SARS cases were under telephone surveillance for 21 days; all probable SARS inpatients and selected suspect SARS inpatients who recovered and were discharged were on home quarantine for 14 days (MMWR 52; 405-11).

Infection Control in Healthcare Settings

General Measures

Hospital workers remain on the front lines in the global response to SARS. They are at considerable risk of contracting SARS when there is an opportunity for unprotected exposure. In order to protect healthcare workers and to prevent disease dissemination, strict infection control measures and public education are essential (Chan-Yeung).

In the SARS hospitals, all healthcare workers should have mandatory body temperature recording twice daily (Mukherjee).

In non-SARS hospitals, in order to minimize patient contact and deal with the potential increased workload from the SARS hospital, all elective surgery is cancelled, as are most outpatient clinics. In order to protect themselves, staff are required to wear an N95 mask, gloves and gown when in contact with all patients. Every attempt is made to streamline workflow to minimize the number of staff in contact with a patient and the time spent with a patient. Because of the potential risk of an individual healthcare worker contaminating a whole department of colleagues, medical units have been divided into small teams who do not have any contact with the other team. Some departments have mandated that one team must be at home to ensure that if another team is quarantined because of exposure, there will still be a clean team available to continue emergency work (Mukherjee).

Other measures include stopping hospital visitations, except for pediatric, obstetric, and selected other patients. For these patients, visitors are limited to a single person who must wear a mask and pass a temperature check; all other visits are by video conference. An audit of infection control practices is ongoing (Mukherjee).

Eventually, appropriate respiratory precautions will be instituted when assessing patients with undifferentiated respiratory conditions and their family members, in order to prevent the introduction of SARS in the hospital setting (Booth).

Protective Measures

Droplet infection seems to be the primary route of spread for the SARS virus in the healthcare setting (Seto). In a case control study in five Hong Kong hospitals, with 241 non-infected and 13 infected staff with documented exposures to 11 index patients, no infection was observed among 69 healthcare workers who reported the use of mask, gloves, gowns, and hand washing. N95 masks provided the best protection for exposed healthcare workers, whereas paper masks did not significantly reduce the risk of infection (Seto).

Table 1 shows a summary of precautions for droplet infection. The implementation of aggressive infection control measures was effective in preventing the further transmission of SARS (Hsu).

Table 1: Precautions for droplet infection (from Chan-Yeung, Outbreak of severe acute respiratory syndrome in Hong Kong Special Administrative Region: case report.)

  • Patients should wear N-95 masks once symptoms develop and be placed immediately in isolation facilities with negative pressure.
  • Healthcare workers should wear similar masks together with head cover, goggles, gowns, and gloves when caring for these patients.
  • Daily and terminal disinfection should be thorough, with careful washing and disinfection of the bed, handrails, bedside tables, floor, and equipment with hypochlorite solution (1000 ppm).
  • For intubated patients, the use of a closed suction system is essential to avoid air leakage and enhanced disease transmission.
  • For detailed information, see the CDC guidelines further below.

    As the SARS virus may be viable in the environment for several days, precautionary measures, including rigorous disinfection and hygiene procedures should provide the highest standard of protection.

    Hand washing

    It is essential to wash hands before touching faces or eyes.

    Gloves

    Health Canada advises double gloving when attending a suspected SARS patient. Hands must be washed after de-gloving.

    Face Masks

    The N95 respirator/mask has a filter efficiency level of 95% or greater against particulate aerosols free of oil when tested against a 0.3 micron particle. It is fluid resistant, disposable and may be worn in surgery. The "N" means "Not resistant to oil". The "95" refers to a 95% filter efficiency. The following points have to be kept in mind (Health Canada):

    • An occlusive fit and a clean shave for men provide the best protection for the healthcare worker.
    • Masks should be tested for fit according to the manufacturer's recommendations. In addition, masks should be fit-checked each time the mask is put on. To check the mask, the wearer takes a quick, forceful inspiration to determine if the mask seals tightly to the face.
    • For instructions on how best to use the N95 mask or equivalent, refer to the handout provided by the manufacturer, or follow your provincial regulations.
    • There are no published data on the length of time the mask is effective for the wearer. Health Canada recommends masks should be changed if they become wet, interfere with breathing, are damaged or visibly soiled.
    • A respirator (mask) which has been exposed to a probable SARS case is considered contaminated and should be discarded.
    • When discarding the mask: Wash hands prior to handling the mask. Carefully remove the mask using the straps. Discard. Wash hands after handling the mask.
    • If re-using the mask: Place in a clean, dry location such as a paper bag. Do not mark the mask with a pen or marker. The name of the owner should be written on the outside of the paper bag to identify the mask. Hands should be washed after handling the mask.

    Even for doctors in the community, it is advisable to wear a N95 mask when seeing any patient with respiratory symptoms (Chan-Yeung).

    Additional protection

    Theatre caps may reduce the risk of staff potentially contaminating their hands by touching their hair. The nature of the novel coronavirus is such that mucous membrane and eye spread is likely and therefore disposable fluid-resistant long sleeved gowns, goggles and disposable full-face shields are recommended for frontline medical staff at risk of exposure to SARS (Kamming).

    Getting undressed

    Getting undressed may seem easier than it is. The sequence that has to be followed - gloves first, gown next, wash your hands, take off your face shield, then the mask, wash you hands again, etc. - requires previous exercise. Some healthcare workers have contracted the SARS virus although they had been using all recommended precautions.

    Special Settings

    Patients who are experiencing rapid clinical progression with a severe cough during the second week of illness should be considered particularly infectious. Procedures that might generate aerosols (e.g. nebulized medications, BiPAP, or HFOV) should be avoided if possible. When intubation is necessary, measures should be taken to reduce unnecessary exposure to health care workers, including reducing the number of health care workers present and adequately sedating or paralyzing the patient to reduce the cough (MMWR; 52: 433-6).

    All high-risk procedures should be performed only by highly experienced staff.

    Intensive Care Units

    A brief summary of infection control measures in intensive care units (grouping critically ill patients with SARS in one ICU; transferring all pre-existing patients to other uncontaminated centers; the ICU restricted to patients with SARS; instructions to staff and visitors to put on gowns, gloves, caps, and masks in a designated area before they enter the unit; designation of "police nurses"; spot checks to ensure the correct fitting of masks; goggles and visors are worn during direct patient care, etc.) has been published by Li et al.

    The use of nebulizer medications should be avoided in SARS patients (Dwosh).

    Intubating a SARS Patient

    In some high-risk instances (i.e., endotracheal intubation, bronchoscopy, sputum induction) airborne transmission may be possible, resulting in exposure to a particularly high viral load.

    The best summary of the measures that need to be taken to minimize the risk to the anesthetist when intubating a suspected SARS patient, were recently published by Kamming, Gardam and Chung from the Toronto Western Hospital (Kamming et al.):

    1. Plan ahead. It takes 5 min to fully apply all barrier precautions.

    2. Apply N95 mask, goggles, disposable protective footwear, gown and gloves. Put on the belt-mounted AirMateä and attach the respirator tubing and Tyvek© head cover. Then apply extra gown and gloves. All staff assisting to follow same precautions. If a powered respirator is unavailable, then apply N95 mask, goggles, disposable theatre cap, and a disposable full-face shield.

    3. Most experienced anaesthetist available to perform intubation.

    4. Standard monitoring, i.v. access, instruments, drugs, ventilator and suction checked.

    5. Avoid awake fibreoptic intubation unless specific indication. Atomized local anaesthetic will aerosolize the virus.

    6. Plan for rapid sequence induction (RSI) and ensure skilled assistant able to perform cricoid pressure. RSI may need to be modified if patient has very high A- a gradient and is unable to tolerate 30 s of apnoea, or has a contraindication to succinylcholine. If manual ventilation is anticipated, small tidal volumes should be applied.

    7. Five minutes of preoxygenation with oxygen 100% and RSI in order to avoid manual ventilation of patient's lungs and potential aerosolization of virus from airways. Ensure high efficiency hydrophobic filter interposed between facemask and breathing circuit or between facemask and Laerdal bag.

    8. Intubate and confirm correct position of tracheal tube.

    9. Institute mechanical ventilation and stabilize patient. All airway equipment to be sealed in double zip-locked plastic bag and removed for decontamination and disinfection.

    10. Assistant should then wipe down the Tyvek‚ head cover with disinfectant (accelerated hydrogen peroxide is most effective) after exiting the negative-pressure atmosphere. The protective barrier clothing is then removed paying close attention to avoid self-contamination. The outer gloves are used to remove the outer gown and protective overshoes. The outer gloves are then discarded and the inner gloves remove the disinfected head cover and the inner gown. The inner gloves are then removed. The head cover is discarded, the AirMate‘ tubing is pasteurized and the belt pack wiped down with disinfectant. The N95 mask and goggles are only removed after leaving the room.

    11. After removing protective equipment, avoid touching hair or face before washing hands.

    Anesthesia

    As specialists in airway management, anesthetists are routinely exposed to patients' respiratory secretions and are at high risk of contracting SARS from infected patients (Kamming).

    Any known or suspected SARS patient must be regarded as ultra high risk and the attending anesthetist should wear a N95 mask, goggles, face shield, double gown, double gloves, and protective overshoes. Removal and disposal of these items without contaminating oneself is critical. The use of a powered respirator by the anesthetist and assistant is strongly advised for high-risk aerosol-generating airway procedures in suspected SARS patients (Kamming).

    Triage

    Identifying persons who might be at risk of SARS on arrival at a medical facility or office is difficult and requires changes in the way medical evaluations are conducted. Revised interim guidelines for triage recommend that all patients in ambulatory-care settings be screened promptly for fever, respiratory symptoms, recent travel, and close contact with a suspected SARS patient:


    Internet Sources

    Infection-control practitioners, clinicians providing medical care for patients with suspected SARS, and persons who might have contact with persons with suspected SARS should frequently consult the CDC's "SARS Infection Control and Exposure Management" guidelines (http://www.cdc.gov/ncidod/sars/ic.htm):

    See also the article "Infection Control Guidance for Handling of Human Remains of Severe Acute Respiratory Syndrome (SARS) Decedents" published by Heath Canada at http://SARSReference.com/link.php?id=17

    CDC: Updated Interim Domestic Infection Control Guidance in the Health-Care and Community Setting for Patients with Suspected SARS

    Revised: May 1, 2003

    Check regularly for updates: http://www.cdc.gov/ncidod/sars/infectionc ontrol.htm

    For all contact with suspect SARS patients, careful hand hygiene is urged, including hand washing with soap and water; if hands are not visibly soiled, alcohol-based handrubs may be used as an alternative to hand washing.

    Access www.cdc.gov/handhygiene for more information on hand hygiene.

    For the inpatient setting:

    If a suspect SARS patient is admitted to the hospital, infection control personnel should be notified immediately. Infection control measures for inpatients (www.cdc.gov/ncidod/hip/isolat/isolat.htm) should include:

    • Standard precautions (e.g., hand hygiene); in addition to routine standard precautions, health-care personnel should wear eye protection for all patient contact.
    • Contact precautions (e.g., use of gown and gloves for contact with the patient or their environment)
    • Airborne precautions (e.g., an isolation room with negative pressure relative to the surrounding area and use of an N-95 filtering disposable respirator for persons entering the room)

    If airborne precautions cannot be fully implemented, patients should be placed in a private room, and all persons entering the room should wear N-95 respirators. Where possible, a qualitative fit test should be conducted for N-95 respirators; detailed information on fit testing can be accessed at http://SARSReference.com/link.php?id=4. If N-95 respirators are not available for health-care personnel, then surgical masks should be worn. Regardless of the availability of facilities for airborne precautions, standard and contact precautions should be implemented for all suspected SARS patients.

    For the outpatient setting:

    • Persons seeking medical care for an acute respiratory infection should be asked about possible exposure to someone with SARS or recent travel to a SARS-affected area. If SARS is suspected, provide and place a surgical mask over the patient’s nose and mouth. If masking the patient is not feasible, the patient should be asked to cover his/her mouth with a disposable tissue when coughing, talking or sneezing. Separate the patient from others in the reception area as soon as possible, preferably in a private room with negative pressure relative to the surrounding area.
    • All health-care personnel should wear N-95 respirators while taking care of patients with suspected SARS. In addition, health care personnel should follow standard precautions (e.g., hand hygiene), contact precautions (e.g., use of gown and gloves for contact with the patient or their environment) and wear eye protection for all patient contact.

    For more information, see the triage guidelines (http://www.cdc.gov/ncidod/sars/triage_interim_guidance.htm).

    For home or residential setting:

    Placing a surgical mask on suspect SARS patients during contact with others at home is recommended. If the patient is unable to wear a surgical mask, it may be prudent for household members to wear surgical masks when in close contact with the patient. Household members in contact with the patient should be reminded of the need for careful hand hygiene including hand washing with soap and water; if hands are not visibly soiled, alcohol-based handrubs may be used as an alternative to hand washing. For more information, see the household guidelines, http://www.cdc.gov/ncidod/sars/ic-closecontacts.htm.

    Case Definition for suspected Severe Acute Respiratory Syndrome (SARS)

    Health-care personnel should apply appropriate infection control precautions for any contact with patients with suspected SARS. The case definition for suspected SARS is subject to change, particularly concerning travel history as transmission is reported in other geographic areas; the most current definition can be accessed at the Severe Acute Respiratory Syndrome (SARS) case definition web page, http://www.cdc.gov/ncidod/sars/casedefinition.htm.

    Additional information

    A power point file summarizing public health interventions has recently been presented at the WHO's Kuala Lumpur meeting:

    "Severe Acute Respiratory Syndrome: Response from Hong", by Yeoh EK: http://SARSReference.com/link.php?id=14

    Infection Control in Households

    Healthcare workers should have a high index of suspicion if they or family members develop fever and features suggestive of severe acute respiratory syndrome. They should present themselves to hospitals rather than treating themselves at home and putting their family members at risk (Chan-Yeung).

    To prevent secondary transmission, close contacts of SARS patients should be vigilant for fever or respiratory symptoms. If such symptoms develop, exposed persons should avoid contact with others, seek immediate medical attention, and practice the infection control precautions that are recommended for SARS patients. Household members and other close contacts of SARS patients should be actively monitored by the local health department for illness.

    Consult frequently CDC's "SARS Infection Control and Exposure Management" guidelines, http://www.cdc.gov/ncidod/sars/ic.htm:

    Contacts of proven cases should isolate themselves until the incubation period is over. After contact with patients with respiratory symptoms, careful hand hygiene is necessary, including washing with soap and water.

    CDC: Interim Guidance on Infection Control Precautions for Patients with Suspected Severe Acute Respiratory Syndrome (SARS) and Close Contacts in Households

    Revised: April 29

    Check regularly for updates:

    http://www.cdc.gov/ncidod/sars/ic-closeco ntacts.htm

    Patients with SARS pose a risk of transmission to close household contacts and health care personnel in close contact. The duration of time before or after onset of symptoms during which a patient with SARS can transmit the disease to others is unknown. The following infection control measures are recommended for patients with suspected SARS in households or residential settings. These recommendations are based on the experience in the United States to date and may be revised as more information becomes available.

    1. SARS patients should limit interactions outside the home and should not go to work, school, out-of-home child care, or other public areas until 10 days after the resolution of fever, provided respiratory symptoms are absent or improving. During this time, infection control precautions should be used, as described below, to minimize the potential for transmission.
    2. All members of a household with a SARS patient should carefully follow recommendations for hand hygiene (e.g., frequent hand washing or use of alcohol-based hand rubs), particularly after contact with body fluids (e.g., respiratory secretions, urine, or feces). See the "Guideline for Hand Hygiene in Health-Care Settings" at http://www.cdc.gov/handhygiene/ for more details on hand hygiene.
    3. Use of disposable gloves should be considered for any direct contact with body fluids of a SARS patient. However, gloves are not intended to replace proper hand hygiene. Immediately after activities involving contact with body fluids, gloves should be removed and discarded and hands should be cleaned. Gloves must never be washed or reused.
    4. Each patient with SARS should be advised to cover his or her mouth and nose with a facial tissue when coughing or sneezing. If possible, a SARS patient should wear a surgical mask during close contact with uninfected persons to prevent spread of infectious droplets. When a SARS patient is unable to wear a surgical mask, household members should wear surgical masks when in close contact with the patient.
    5. Sharing of eating utensils, towels, and bedding between SARS patients and others should be avoided, although such items can be used by others after routine cleaning (e.g., washing with soap and hot water). Environmental surfaces soiled by body fluids should be cleaned with a household disinfectant according to manufacturer's instructions; gloves should be worn during this activity.
    6. Household waste soiled with body fluids of SARS patients, including facial tissues and surgical masks, may be discarded as normal waste.
    7. Household members and other close contacts of SARS patients should be actively monitored by the local health department for illness.
    8. Household members or other close contacts of SARS patients should be vigilant for the development of fever or respiratory symptoms and, if these develop, should seek healthcare evaluation. In advance of evaluation, healthcare providers should be informed that the individual is a close contact of a SARS patient so arrangements can be made, as necessary, to prevent transmission to others in the healthcare setting. Household members or other close contacts with symptoms of SARS should follow the same precautions recommended for SARS patients.
    9. At this time, in the absence of fever or respiratory symptoms, household members or other close contacts of SARS patients need not limit their activities outside the home.

    Related Links:

    SARS Information for Patients and Their Close Contacts, http://www.cdc.gov/ncidod/sars/closecontacts .htm

    Possible Transmission from Animals

    SARS Co-V was found in three animal species taken from a market in Southern China (masked palm civet and racoon-dog, Chinese ferret badger). As a precautionary measure, persons who might come into contact with these species or their products, including body fluids and excretions, should be aware of the possible health risks, particularly during close contact such as handling and slaughtering and possibly food processing and consumption (WHO Update 64).

    After the Outbreak

    When the Toronto epidemic was already thought to be over, an undiagnosed case at the North York General Hospital led to a second outbreak among other patients, family members and healthcare workers.

    Infection control measures may have been lifted too early. During early and mid-May, as recommended by provincial SARS-control directives, hospitals discontinued SARS-expanded precautions (i.e., routine contact precautions with use of a N95 or equivalent respirator) for non-SARS patients without respiratory symptoms in all hospital areas other than the emergency department and the intensive care unit (ICU). In addition, staff were no longer required to wear masks or respirators routinely throughout the hospital or to maintain distance from one another while eating. In the hospital where the second outbreak originated, changes in policy were instituted on May 8; the number of persons allowed to visit a patient during a 4-hour period remained restricted to one, but the number of patients who were allowed to have visitors was increased (MMWR; 52:547-50).

    Maintaining a high level of suspicion for SARS on the part of healthcare providers and infection-control staff is therefore critical, particularly after a decline in reported SARS cases. The prevention of healthcare-associated SARS infections must involve health care workers, patients, visitors, and the community (MMWR; 52:547-50).

    Conclusion

    One of the most important lessons learned to date is the decisive power of high-level political commitment to contain an outbreak even when sophisticated control tools are lacking. SARS has been brought close to defeat by the diligent and unrelenting application – on a monumental scale – of centuries-old control measures: isolation, contact tracing and follow-up, quarantine, and travel restrictions. Other successful measures include the designation of SARS-dedicated hospitals to minimize the risk of spread to other hospitals, mass media campaigns to educate the public and encourage prompt reporting of symptoms, and the establishment of fever clinics to relieve pressure on emergency rooms, which have also been the setting for many new infections. Screening at airports and other border points and, thorough fever checks throughout selected population groups has also been effective (WHO Update 83).

    All of these measures contributed to the prompt detection and isolation of new sources of infection – a key step on the way to breaking the chain of transmission. Given the importance of supportive public attitudes and actions, the single most important control "tool" in bringing SARS under control may very well be the thermometer (WHO Update 83).


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