WHO SARS Risk Assessment and Preparedness Framework

WHO SARS Risk Assessment andPreparedness Framework

October 2004

Department of Communicable DiseaseSurveillance and Response

WHO/CDS/CSR/ARO/2004.2

© World Health Organization 2004

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WHO SARS Risk Assessment and Preparedness Framework October 2004

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Contents

Executive summary..................................................................................................................3

1. Introduction..........................................................................................................................4

Using the "WHO SARS Risk Assessment and Preparedness Framework".............................................................5 Summary of the role of WHO and national health authorities in SARS preparedness and response .....................6

The role of WHO ..................................................................................................................................6 The role of national health authorities ..................................................................................................7

Assessing the level of risk from the re-emergence of SARS-like coronaviruses during inter-epidemic periods......7 Global risk assessment for the inter-epidemic period .............................................................................7 Indicators for the escalation of the risk of SARS....................................................................................8

2. Phases of the SARS preparedness framework ..................................................................10

Preparedness levels .............................................................................................................................................. 10 Alerting the international community of the re-emergence of SARS..................................................................... 10 Reporting to WHO ................................................................................................................................................. 11

3. Phase 0 – Inter-epidemic period: No evidence of SARS - CoV transmission to humans worldwide...........................................................................................................................12

Phase 0 – Preparedness planning and response activities: WHO........................................................................ 12 Alert, verification and response activities ........................................................................................... 12 Planning ............................................................................................................................................ 13

Phase 0 – Preparedness planning and response activities: National health authorities....................................... 14 Alert, verification and response activities ........................................................................................... 14 Planning ............................................................................................................................................ 15

4. Phase 1 – Inter-epidemic period: Sporadic case(s) of SARS .............................................17

Phase 1 – Response: WHO .................................................................................................................................. 18 Phase 1 – Response: Countries/areas reporting SARS cases ............................................................................. 18

Outbreak affecting a laboratory .......................................................................................................... 19 Phase 1 – Response: Countries/areas free of SARS............................................................................................ 19

5. Phase 2 – Confirmed human-to-human transmission ........................................................20

Phase 2, Level 1 – Chain(s) of transmission in one location................................................................................. 20 Phase 2, Level 1 – Response: WHO..................................................................................................................... 20 Phase 2, Level 1 – Response: Countries/areas reporting SARS cases ............................................................... 21

Outbreak affecting a health-care facility ............................................................................................. 21 Phase 2, Level 1 – Response: Countries/areas free of SARS.............................................................................. 21 Phase 2, Level 2 – Chains of transmission in two or more locations with no evidence of international spread ... 22


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Phase 2, Level 2 – Response: WHO..................................................................................................................... 22 Phase 2, Level 2 – Response: Countries/areas reporting SARS cases ............................................................... 23

Outbreak affecting a health-care facility ............................................................................................. 23 Phase 2, Level 2 – Response: Countries/areas free of SARS.............................................................................. 24

6. Phase 3 – International spread of SARS ............................................................................25

Phase 3 – Response: WHO .................................................................................................................................. 25 Phase 3 – Response: Countries/areas reporting SARS cases ............................................................................. 26 Phase 3 – Response: Countries/areas free of SARS............................................................................................ 26

7. Phase 4 – Slowing down of the outbreak...........................................................................27

Phase 4 – Response: WHO .................................................................................................................................. 27 Phase 4 – Response: Countries/areas reporting SARS cases ............................................................................. 27 Phase 4 – Response: Countries/areas free of SARS............................................................................................ 27

8. Phase 5 – Global interruption of SARS-CoV transmission (epidemic halted)....................28

Phase 5 – Response: WHO .................................................................................................................................. 28 Phase 5 – Response: Countries/areas reporting SARS cases ............................................................................. 29 Phase 5 – Response: Countries/areas free of SARS............................................................................................ 29 References...........................................................................................................................30


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Executive summary

This document sets out a framework of activities, at national and international levels, that can be used to assess the risk that SARS might recur and to prepare appropriate contingency plans. Modelled on WHO’s influenza pandemic preparedness plan, the framework adopts a phased approach in which recommended activities escalate in line with the evolving epidemiological situation. Phases are defined by distinct epidemiological criteria, such as the detection of sporadic cases with no secondary spread, the establishment of human-to-human transmission, and evidence of international spread. The possibility that the SARS coronavirus might behave differently than during the 2002–2003 international outbreak is also taken into account. WHO strongly recommends that all countries undertake a risk assessment as the basis for contingency plans, as SARS-related risks will vary considerably both within and between countries. In issuing the framework, WHO aims to help countries match the level of risk with appropriate activities and thus avoid introducing costly and demanding measures that are not justified by the epidemiological situation. The framework is organized according to six phases, moving from the inter-epidemic period, when preparedness planning and routine surveillance for cases are stressed, through the establishment of chains of transmission and subsequent international spread, to global interruption of transmission. For each phase, activities are listed separately for countries/areas reporting SARS cases and countries/areas free of SARS. Examples of activities range from a review of the legal framework to ensure its compatibility with control measures, through an inventory of laboratories working with SARS or storing clinical specimens, to factors to consider when deciding whether to close a health care facility. Also indicated are the activities, at each phase, that will be undertaken by WHO and the types of assistance that WHO can provide to countries. Taken together, these lists of activities should serve as a useful tool for formulating contingency plans that are adequately protective and appropriate to the level of risk.


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1. Introduction

The natural reservoir of SARS-CoV has not been identified but a number of wildlife species, the Himalayan masked palm civet (Paguma larvata), the Chinese ferret badger (Melogale moschata), and the raccoon dog (Nyctereutes procyonoides) consumed as delicacies in southern China have shown laboratory evidence of infection with a related coronavirus (1,7). Domestic cats living in the Amoy Gardens apartment block in Hong Kong were also found to be infected with SARS-CoV (8). More recently, ferrets (Mustela furo) and domestic cats (Felis domesticus), were infected with SARS-CoV experimentally and found to efficiently transmit the virus to previously uninfected animals housed with them (9). These findings indicate that the reservoir for this pathogen may involve a range of animal species. At the time of writing, the masked palm civet is the wildlife species most often associated with animal-to-human transmission; however, whether this species is the natural reservoir of SARS-like coronaviruses remains unproven. On 5 July 2003, the World Health Organization (WHO) reported that the last human chain of SARS transmission had been broken. At the time of writing in October 2004, the world is in an inter-epidemic period for SARS. At this time the most probable sources of infection with SARS-CoV are exposure in laboratories where the virus is used or stored for diagnostic and research purposes, or from animal reservoirs of SARS-CoV-like viruses. Since July 2003, there have been four occasions when SARS has reappeared. Three of these incidents were attributed to breaches in laboratory biosafety and resulted in one or more cases of SARS [Singapore (10–12), Taipei (13) and Beijing (14,15)]. The most recent laboratory incident resulted in 9 cases, 7 of which were associated with one chain of transmission and with hospital spread. Two additional cases at the same laboratory with a history of illness compatible with SARS in February 2004 were detected as part of a serosurvey of contacts at the facility. The fourth incident [Guangzhou, Guangdong province, China (16–18)] resulted in four sporadic community-acquired cases arising over a six-week period. Three of those cases were attributed to exposure to animal (19,20) or environmental sources while the source of exposure is unknown in the other case. There was no further community transmission. It remains very difficult to predict when or whether SARS will re-emerge in epidemic form. The 2002–2003 epidemic was characterized by "superspreading events" (21–27) which seeded outbreaks in Canada, the People’s Republic of China, the Hong Kong Special Administrative Region of China, Taiwan, China, Singapore and Viet Nam. Health-care systems in areas with sustained transmission of SARS were rapidly overburdened and public health systems in countries free of SARS investigating cases of SARS-like illness were also severely stressed by the increased workload. If SARS does recur, early detection of infected individuals will be crucial to contain the spread of infection and prevent international spread. The responsibility for managing the risk of SARS re-emergence or introduction rests primarily with national authorities. WHO strongly recommends that all countries undertake an analysis of their risk and

Severe acute respiratory syndrome (SARS) is a newly identified acute viral respiratory syndrome caused by a novel coronavirus, the SARS coronavirus (SARS-CoV) which is believed to have crossed the species barrier recently from animals to humans (1– 4). The first case was retrospectively recognized as having occurred in Guangdong Province, China, in November 2002 (2, 5). By July 2003, the international spread of SARS-CoV resulted in 8098 SARS cases in 26 countries, with 774 deaths (6). The epidemic caused significant social and economic disruption in areas with sustained transmission of SARS, and on the travel industry internationally, in addition to the impact on health services directly.


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develop a contingency plan for the detection and management of SARS. In recognition that this risk varies between and within countries, this document does not provide a "model plan" but identifies roles and activities for WHO and national health authorities. Countries that assess their risk as high may establish and/or maintain a National SARS Taskforce or Technical Advisory Committee for preparedness planning and response, while in low risk areas integrated alert and response systems for acute respiratory diseases, including SARS, may be the most cost-effective approach to the continued vigilance for SARS.

Using the "WHO SARS Risk Assessment and Preparedness Framework"

This Framework should be used in conjunction with national preparedness and response guidance. WHO recognizes that the risk of SARS varies between and within countries and regions of the world so that strategies for detecting and responding to SARS, and the resources allocated, will vary according to the national risk assessment. The non-specific clinical features of SARS, the lack of a current diagnostic test that can reliably detect SARS-CoV in the first few days of illness, and the seasonal occurrence of other respiratory diseases, including influenza, may result in "false alarms" or demand a level of surveillance sensitivity and intensity which few health-care systems worldwide can sustain. To better cope with false alarms resulting from heightened surveillance for SARS, a series of preparedness levels (phases) has been defined in the Framework to assist WHO to report on the risk of SARS at the global level and initiate responses in collaboration with national health authorities. Accordingly, this document has been prepared for decision-makers, clinicians and public health professionals to assist their response to future threats from the re-emergence of SARS. It outlines the separate but complementary roles and responsibilities of the WHO and national health authorities when the re-emergence of SARS appears possible or actually occurs. This document should be used in conjunction with the following publications: 1. WHO guidelines for the global surveillance of SARS. Updated recommendations October 2004 (28)

which presents WHO revised surveillance strategy for SARS in the inter-epidemic period, once a chain of human transmission has been laboratory confirmed and during a sustained outbreak.

2. Infection control and clinical management of Severe Acute Respiratory Syndrome (SARS)–A continuing concern for all health-care workers. This document will be published on the WHO web site in December 20041.

3. The SARS minimum global data dictionary. This document is under development. Refer to the WHO web site on severe acute respiratory syndrome (SARS) on which new documents are published1 .

1 http://www.who.int/csr/sars/en/index.html


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Summary of the role of WHO and national health authorities in SARS preparedness and response

If SARS re-emerges it may only result in sporadic cases, there may be small, localized chains of transmission, a multi-focal outbreak of longer duration in one country, or international spread. Accordingly, national and international responses will need to be flexible and proportionate to the escalating level of risk. WHO will assist national health authorities in undertaking their risk assessment and in facilitating technical cooperation and laboratory testing if requested.

The role of WHO

• Coordinating global and regional surveillance, including rumour alert and verification.

• Maintaining a minimum global data set for case reporting and epidemiological analysis.

• Maintaining up-to-date summary reports on SARS activity on the WHO web sites and addressing media inquiries.

• Undertaking global risk assessment and risk communication and assisting countries in national risk assessment if required.

• Developing guidance documents, updated as new knowledge about SARS becomes available, to assist global and national policy formulation and programme implementation.

• Assisting countries in national capacity development for disease surveillance and outbreak response.

• Providing quality assurance in laboratory diagnostics, including the distribution of proficiency panels and reagents, and independent verification through the WHO SARS International Reference and Verification Laboratory Network.

• Assisting countries in national capacity development in the areas of infection control, laboratory management, laboratory biosafety, and occupational health and safety as required.

• Assessing the availability of stockpiles (personal protective equipment [PPE], laboratory reagents, therapeutic agents, other consumables, and vaccines when available) and contingency funds for outbreak response.

• Facilitating technical cooperation through the Global Outbreak Alert and Response Network (GOARN) and the WHO SARS virtual networks (Clinical Management/Clinical Trials, Laboratory, Epidemiology, Animal Reservoir, Food Safety, Environmental Health and Vaccine Development). WHO continues to mobilize technical support to field investigations through GOARN.

• Facilitating international scientific collaboration and funding for the public health research priorities for SARS through mechanisms such as the SARS Research Advisory Committee.


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The role of national health authorities

Assessing the level of risk from the re-emergence of SARS-like coronaviruses during inter-epidemic periods

Global risk assessment for the inter-epidemic period

Ideally, each national government should undertake a SARS risk assessment in the inter-epidemic period to determine which surveillance strategy is the most appropriate, feasible and cost-effective for the country’s level of risk.

• Primary responsibility for undertaking a national SARS risk assessment and managing that risk. • Establishing an effective SARS response management process and the chain of command by assigning

specific roles and responsibilities to key agencies (preventive, curative and diagnostic services) for the investigation, verification, clinical and public health management of SARS. This may involve establishing a National SARS Taskforce if the risk of SARS-CoV re-emergence or introduction is considered high.

• Developing a SARS preparedness and response plan or incorporating SARS in an integrated preparedness and response plan for epidemic-prone diseases depending on the risk assessment. This should include criteria for stepping down the national response.

• Reviewing and revising public health legislation to facilitate the investigation, verification, containment and control of SARS and other dangerous pathogens.

• Establishing or strengthening SARS-specific surveillance systems or integrated early warning systems depending on the risk assessment, including laboratory surveillance if appropriate.

• Training groups occupationally at risk of SARS-CoV infection in the prevention and early recognition of the clinical presentation of SARS, and the appropriate actions to take in the event of a SARS-like illness.

• Training clinical, laboratory and public health professionals to prevent, investigate, treat, contain and control SARS.

• Assessing standards of hospital infection control, including infection control during radiological procedures.

• Assessing standards of laboratory management, laboratory biosafety and occupational health and safety, and improving standards if required.

• Developing monitoring and accreditation systems as part of quality assurance for hospitals and laboratories in the public and private sectors.

• Ensuring supplies of personal protective equipment, other essential equipment and pharmaceuticals, and logistics.

• Educating the public about the symptoms and signs of SARS, risk factors for infection, personal measures of prevention including respiratory and contact precautions, and the rationale behind control measures.

• Mobilizing the community in prevention and control measures.

• Communicating risk. • Participating in international collaborations for SARS prevention, containment and control and in

applied research as appropriate.


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WHO has defined three situations that take into account global experience during the 2002–2003 SARS epidemic and the potential for SARS emergence (see Table 1).

Table 1. Risk categories for the emergence of SARS

Risk category Definition

Emergence of SARS-CoV-like viruses from wildlife or other animal reservoirs

Countries/areas identified as source(s) of the epidemic in 2002–2003 in southern China or areas with an increased likelihood of animal-to-human transmission of SARS-CoV-like viruses from wildlife or other animal reservoirs.

Emergence or introduction of SARS-CoV from laboratories or through international travel

Countries/areas at potentially higher risk of SARS-CoV emergence or introduction due to the presence of laboratories in which SARS-CoV and/or SARS-CoV-like viruses are being studied or in which clinical specimens infected with SARS-CoV are being processed or stored.

OR

Countries/areas with entry of large numbers of persons from areas in which wildlife or other animal reservoirs of SARS-CoV-like viruses are found.

Low risk of SARS-CoV emergence or introduction

Countries/areas that never reported cases or reported only imported cases during the 2002–2003 epidemic, and that do not conduct research using live SARS-CoV-like viruses or store clinical samples from SARS cases

Note: Some countries/areas may fall into two risk categories.

Indicators for the escalation of the risk of SARS

This Framework and related documents use the term "inter-epidemic period" rather than "post-epidemic period" because of the ongoing uncertainty about whether the world will experience another multi-jurisdictional epidemic of SARS. The reappearance of SARS-CoV may herald another epidemic with characteristics similar to the 2002–2003 epidemic. Effective planning for SARS must therefore include a process that escalates the level of response at national, regional and global levels based on a set of measurable determinants of risk.


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In addition, the response must be flexible enough to adapt quickly to new health intelligence.

While some of the risk determinants listed below are hypothetical at the time of writing in October 2004, they have been included for completeness:

• The source and route(s) of transmission, and whether they have been identified and contained.

• Evidence of human chains of SARS-CoV transmission of more than two generations, especially when secondary cases occur outside the group of known contacts of the source case(s).

• The size of the outbreak and the rate of increase of new cases.

• Evidence of international spread. A single exported case of SARS constitutes international spread.

• The geographical location, including the risk of SARS-CoV re-emergence or emergence, the mobility of local populations and whether the site is an international hub for travel or trade.

• The relative strength of acute medical and public health infrastructure, especially surveillance and response capacity.

• Evidence of increased virulence of SARS-CoV, increased transmissibility or spread by previously unknown or uncommon route(s) of transmission.

• Evidence of diminished efficacy of containment and control measures effective during the 2002–2003 epidemic.

• Evidence of endemicity in a country or area.

• Evidence of animal-to-animal or human-to-animal transmission of SARS-CoV/SARS-CoV-like viruses to companion animals and/or feral animals living in close proximity to humans.


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2. Phases of the SARS preparedness framework

Preparedness levels

Table 2 . Preparedness levels for inter-epidemic, epidemic and post-epidemic periods

Phase Epidemiological situation

Phase 0 No evidence of SARS-CoV transmission to humans worldwide.

Phase 1 Sporadic case(s) of SARS or a common source of transmission that does not result in secondary cases.

Phase 2 Confirmed human-to-human transmission. The magnitude of the outbreak is described in Phase 2, Levels 1 and 2.

Phase 2, Level 1 Chain(s) of transmission in one location.

Phase 2, Level 2 Chains of transmission in two or more locations but with no evidence of international spread.

Phase 3 International spread.

Phase 4 Slowing down of the outbreak.

Phase 5 Global interruption of SARS-CoV transmission (epidemic halted).

Alerting the international community of the re-emergence of SARS

WHO will alert the international community in the event of the reappearance of SARS and if there is any phase shift. This alert will be issued via well-established mechanisms by WHO, i.e. the Outbreak Verification List (OVL), the WHO Outbreak News on the WHO HQ web site, Regional Office web sites,

In this framework, the phase refers to stages that might be seen in a SARS outbreak. These are defined below (Table 2). The activities assigned to WHO, countries/areas with sustained transmission of SARS and countries/areas without cases are incremental as the level of risk escalates. In Phases 0–1, WHO and national health authorities should direct efforts towards assessing preparedness and developing contingency plans. Phases may occur in a non-sequential fashion; for example, laboratory confirmation of SARS in a cluster of cases of acute respiratory infection (ARI) would result in a shift from Phase 0 (no evidence of SARS-CoV transmission to humans worldwide) to either Phase 1 if there is a common source of transmission or directly to Phase 2 (confirmed human-to-human transmission).


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the Weekly Epidemiological Record, media releases, media interviews, and via direct communication between WHO Regional and Country Offices and national health authorities as required.

Outbreak Verification List

Disease Outbreak News

The WHO Disease Outbreak News provides public information about officially confirmed outbreaks of international importance. Disease Outbreak News is one of the most frequently accessed web pages on the WHO web site1.

Weekly Epidemiological Record

The Weekly Epidemiological Record (WER) is published in a bilingual French/English edition and issued in print and electronically2. It covers epidemiological information on cases and outbreaks of diseases of public health importance. An Outbreak News section has been added to the WER, mirroring the Disease Outbreak News web page.

Reporting to WHO

The updated WHO surveillance case definitions for SARS are given in WHO guidelines for the global surveillance of SARS. Updated recommendations October 2004 (28). For the purposes of the international reporting of SARS to WHO, national public health authorities are requested to officially report:

• "preliminary positive" cases

• "probable" cases

• "confirmed" cases

• "unverifiable" cases during an outbreak of SARS.

National health authorities should report the first "preliminary positive" case(s) of SARS in their country to WHO within 24 hours of the receipt of positive test results from their national SARS reference laboratory. However, in view of the global attention given to SARS rumours, informing WHO of clusters of ARI and/or high-risk individuals under investigation for SARS will facilitate rapid verification and the accurate dissemination of information to other governments, the media and the public.

1 http://www.who.int/csr/don/en/ 2 http://www.who.int/wer/en/

Reports of current outbreaks of potential international public health concern, either verified or under verification, are included in the weekly WHO Outbreak Verification List (OVL). The OVL provides authoritative information to public health professionals about reports of outbreaks of international public health importance in order to improve epidemic awareness and preparedness and to minimize the risk of inappropriate action.


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3. Phase 0 – Inter-epidemic period: No evidence of SARS- CoV transmission to humans worldwide

Criteria for Phase 0

There is no epidemiological or laboratory evidence that SARS-CoV is circulating in the human population.

Sporadic cases or clusters of unexplained ARI may occur but are discarded as cases of SARS after epidemiological investigation and laboratory testing.

Note: At the time of writing in October 2004, transmission of SARS-CoV from asymptomatically infected individuals has not been reported. However, given the difficulties in diagnosing SARS clinically, all health-care facilities should ensure they are applying standard precautions at all times and adopting additional respiratory precautions when investigating and managing individuals with an acute respiratory illness if indicated on the basis of an assessment of the local population risk and individual risk of SARS.

Evidence to exclude transmission of SARS-CoV to humans in Phase 0 may include:

- Failure to detect SARS by enhanced surveillance for acute respiratory infections (ARI) in areas or populations at higher risk of SARS from wildlife or other animal sources that are the putative reservoirs of SARS-CoV-like viruses, or through their work in a laboratory.

- Serosurveillance data excluding animal-to-human transmission to individuals at occupational risk of exposure to wildlife or other animals (above), their excretions and secretions.

- Serosurveillance data on staff in laboratories working with live SARS-CoV/SARS-CoV-like viruses, or storing clinical specimens from humans or animals infected with such coronaviruses.

- Failure to detect disease or unexplained mortality in wildlife or other animals susceptible to SARS-like coronaviruses.

Phase 0 – Preparedness planning and response activities: WHO

Alert, verification and response activities

• Identify and verify rumours of events of international public health concern, including rumours about SARS, through well-established mechanisms.

• Develop tools to assist in the investigation of SARS (human, animal and environmental sources).

• Assist countries to investigate disease outbreaks on request.

• Facilitate technical cooperation through the Global Outbreak Alert and Response Network (GOARN) and the WHO SARS virtual networks (Clinical Management/Clinical Trials, Laboratory, Epidemiology, Animal Reservoir, Food Safety, Environmental Health and Vaccine development).

• Facilitate international scientific collaboration and funding for the public health research priorities for SARS through mechanisms such as the SARS Research Advisory Committee.


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Planning

Risk assessment, policy and legal frameworks

Surveillance systems

Curative health services • Develop clinical algorithms to assist clinicians in assessing patients with ARI for their risk of SARS. • Develop guidance on the clinical management of SARS and in infection control in the health-care

setting (refer to Infection control and clinical management of severe acute respiratory syndrome (SARS) –A continuing concern for all health-care workers, in preparation. It will be published on the WHO SARS web site).

• Complete the revision of the International Health Regulations to provide a stronger framework for the detection, assessment and coordinated management of risks to global public health.

• Undertake global and regional risk assessments for the emergence or introduction of SARS-CoV.

• Assist countries in their national risk assessment for SARS-CoV and SARS-CoV-like viruses emerging locally, or being introduced, as required.

• Assess the regional and global availability of supplies (PPE, laboratory reagents, therapeutic agents, and vaccines when available) for outbreak response.

• Recommend public health measures on the basis of a continuous review of the evolving knowledge on SARS and publish updated recommendations on WHO web sites and in the scientific literature.

• Work with international partners to evaluate the effectiveness of SARS control measures used during the 2002–2003 epidemic.

• Coordinate global and regional surveillance, including rumour alert and verification.

• Develop and maintain a minimum global data set for case reporting and epidemiological analysis.

• Maintain up-to-date summary reports on SARS-CoV activity on WHO web sites and address media inquiries.

• Assist countries in national capacity development of disease surveillance, verification and outbreak response.

• Facilitate technical cooperation for countries wishing to evaluate, and develop where necessary, infection control programmes in acute curative and long-stay care facilities.

• Provide training in hospital infection control and the correct use of PPE, including the development of multimedia training tools.

• Institute a regional infection control programme as required.


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Laboratories

Social mobilization

Phase 0 – Preparedness planning and response activities: National health authorities

Alert, verification and response activities

• Develop and test SOPs for reporting SARS alerts to hospital infection control staff, local public health units, the national public health authority, the National SARS Taskforce or Technical Advisory Committee if convened, and to WHO (28).

• Promote international quality assurance in laboratory diagnostics, including the distribution of proficiency panels and reagents.

• Strengthen global and regional laboratory networks and develop a regional strategy for the collection, safe handling and transportation of specimens to these laboratories.

• Facilitate linkages between national and regional laboratory networks and the WHO SARS International Reference and Verification Laboratory Network.

• Facilitate access to diagnostic services through the WHO SARS International Reference and Verification Laboratory Network for countries without their own national SARS reference laboratory.

• Assist countries doing research using live SARS-CoV or related viruses, or storing clinical specimens from humans or animals infected with SARS-CoV/SARS-CoV-like viruses, in reviewing laboratory design, infrastructure, laboratory management, biosafety policies and practices, and occupational health and safety programmes, and improving them if required.

• Develop a global risk communication plan.

The range of activities will vary depending on the risk assessment. This will also determine whether SARS-specific activities are required or if SARS is better placed within the programmes and operational structures for other respiratory diseases or emerging and dangerous pathogens.

• Strengthen alert, verification, reporting and response capacity for epidemic-prone diseases, with specific training in responding to the re-emergence, emergence or introduction of SARS-CoV.

• Strengthen training in field epidemiology and promote linkages with the relevant disciplines responsible for clinical epidemiology, hospital infection control, laboratory biosafety, animal health and environmental health.

• Develop standard operating procedures (SOPs) for the investigation, clinical and public health management of patients with ARI with fever based on the national risk assessment for SARS and the local burden of respiratory disease.

• Report high-risk individuals or clusters under investigation for SARS to WHO promptly and transparently. In view of the global attention given to SARS rumours, informing WHO of such events in a timely manner will facilitate rapid verification and the accurate dissemination of information to other governments, the media and the public.

• Consider releasing information on rumours of SARS under investigation to the local media, neighbouring countries and to the WHO virtual network on SARS Epidemiology to actively manage risk communication.


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Planning

Risk assessment, policy and legal frameworks

Surveillance systems

• Review surveillance and reporting systems for SARS and other epidemic-prone diseases. See WHO guidelines for the global surveillance of SARS. Updated recommendations October 2004 (28) for the WHO approach to surveillance for SARS.

Health services mobilization

• Identify acute-care facilities and diagnostic services to manage cases of SARS.

• Train clinical, laboratory and public health professionals to diagnose, treat, contain and control SARS.

• Ensure a supply chain and logistics support for PPE, laboratory reagents, therapeutic agents (and vaccines when available if appropriate) during an outbreak.

• Review, and upgrade where necessary, the standard of infection control in acute curative and long-stay care facilities. Develop a strategy for community-based infection control.

• Review utilization patterns of PPE, laboratory reagents and therapeutic agents and the integrity of the supply chain.

• Maintain a programme of continuing health-care worker education in infection control and the correct use of PPE.

Laboratories

• Participate in national and international quality assurance programmes in SARS diagnostics as appropriate.

• Undertake a national risk assessment for SARS-CoV and related viruses emerging locally or being introduced.

• Review the public health legal framework to enable the investigation and control of SARS and other outbreak-prone diseases.

• Establish an effective SARS response management process at all levels of government and define the chain of command by assigning specific roles and responsibilities to key agencies (public health, curative and diagnostic services) for the investigation, verification, clinical and public health management of SARS.

• Determine the most effective ways of providing human resources and logistics support for outbreak response (surge capacity).

• Consider developing a major event response plan for epidemic-prone diseases.

• Consider developing a database to link clinical, epidemiological and laboratory data.

• Consider developing appropriate evaluation/audit tools for outbreak alert and response operations.

• Establish an inventory of all laboratories working with live SARS-CoV and SARS-CoV-like viruses, or storing clinical specimens from humans or animals infected with these viruses.

• Ensure that all laboratories meet minimum safety standards with respect to design, equipment (including PPE), laboratory management and laboratory practice. Ensure that a regular programme of building and equipment maintenance is in place and monitor compliance.

• Develop links with reference laboratories in other countries, regional reference laboratories and/or the WHO SARS International Reference and Verification Laboratory Network for access to SARS diagnostic and/or reference laboratory functions.


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• Develop and implement health monitoring programmes for all personnel working in laboratories that use SARS-CoV/SARS-CoV-like viruses, clinical materials from SARS patients or infected animals, infectious clones and/or replicons. Health monitoring is relevant to all staff working with infectious agents.

• Establish an OH&S officer position if not already in place, reporting directly to the facility’s senior management and with the authority to enforce changes in staff health policy and practice.

• Vaccinate laboratory workers against vaccine preventable diseases they may be exposed to in the facility. Vaccinate laboratory workers at risk against SARS-CoV when vaccines against SARS have been approved for human use. Consider offering influenza vaccination to all laboratory workers propagating SARS-CoV/SARS-CoV-like viruses, clinical materials from SARS patients or infected animals, infectious clones and/or replicons to help reduce the likelihood of diagnostic confusion between influenza and SARS.

• Develop a regulatory framework for biosafety and occupational health and safety if not already in place, with an independent national regulatory authority to oversee the implementation of these functions and accredit compliant laboratories as part of long term improvements in biosafety and occupational health and safety.

Social mobilization

• Identify training requirements in laboratory biosafety and promote the training of all personnel working with infectious biological agents.

• Ensure that all staff are trained to recognize the common symptoms and signs of the diseases resulting from exposure to the pathogens studied in the facility. This should include fever and respiratory symptoms for SARS, with or without diarrhoea. Any laboratory worker developing a febrile illness should notify their supervisor and Occupational Health and Safety (OH&S) officer promptly and be placed under observation.

• Ensure that all laboratory personnel participate in a health monitoring programme that should include the collection of baseline sera at the time of employment and regular (annual) screening thereafter.

• Develop and test an emergency management plan for the investigation of, and response to, laboratory incidents. This plan should include specific activities and lines of reporting at each level of the organization, from individual laboratory worker to senior management.

• Ensure that the emergency management plan provides for rapid access to medical care for the assessment, clinical management (including post-exposure prophylaxis when relevant) and follow-up of staff involved in laboratory incidents. Access to health services should be available at all times.

• Develop a communication strategy to provide accurate information to the public on risks to health from SARS-CoV, its presenting features, risk factors for exposure, clinical and public health management and preventive measures, including respiratory and contact precautions.

• Educate personnel occupationally at risk of SARS in their responsibility to volunteer details of their occupational history when seeking health care for an acute febrile illness.


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4. Phase 1 – Inter-epidemic period: Sporadic case(s) of SARS


Sporadic (isolated) cases of SARS or a cluster resulting from a common source outbreak have been confirmed by the national SARS reference laboratory in one or more countries ("preliminary positive" cases) and independently verified by a WHO SARS International Reference and Verification Network laboratory ("confirmed" cases).

The case(s) are locally acquired from:

− an environmental source (laboratories working with live SARS-CoV or SARS-CoV-like viruses, or storing clinical specimens from humans or animals infected with such viruses)

OR

− an animal source (inter-species transmission from exposure to wildlife or other animals that are the putative reservoirs of SARS-CoV-like viruses, their excretions and secretions).

Transmission from an unidentified human source case has been excluded as far as possible.

There is no clinical, epidemiological or laboratory evidence of secondary transmission to contacts after an appropriate epidemiological investigation.

Notes:

2. Sporadic cases without an identifiable source of infection after a detailed epidemiological investigation are of greater concern as they may be the result of a missed chain of human transmission or another form of occult exposure. Active case finding around the case is recommended in that situation as well as heightened surveillance for other individuals with clinical evidence of SARS (see WHO guidelines for the global surveillance of SARS. Updated recommendations October 2004 for the clinical criteria for SARS). In this situation, WHO will work with the country to determine whether there should be a shift to Phase 2 (human chains of transmission in one or more locations). Failure to identify a source of infection may be due to false positive test results for SARS-CoV, a missed or occult source of transmission (environmental, animal or human), or a previously unknown source or route of transmission.

1. If the epidemiological and/or laboratory investigations provide compelling evidence that transmission occurred in another country, there will be an automatic shift from Phase 1 to Phase 3 – International spread – until human chain(s) of transmission or a continuing source of SARS-CoV can be excluded in the putative source country.


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Phase 1 – Response: WHO

Phase 1 – Response: Countries/areas reporting SARS cases

• Issue advice to health-care workers and laboratory personnel about any changes to transmission-based precautions, infection control and laboratory biosafety if indicated by the epidemiological investigation.

• Provide technical support directly and/or through the Global Outbreak Alert and Response Network to national governments in the field investigation of the case(s) on request, including mobilizing international expertise to work with local investigation teams.

• Facilitate access to diagnostic services and/or independent verification of laboratory results through the WHO SARS International Reference and Verification Laboratory Network.

• Work with countries to revise the national and international risk assessment based on the results of the field investigations.

• Work with countries on a joint communication strategy to facilitate the accurate dissemination of information to other governments, the media and the public in order to minimize public alarm, social disruption and the adverse impact on economies.

• Maintain up-to-date summary reports on SARS activity on WHO web sites and address media inquiries.

• Activate the national response mechanism (national health authority or National SARS Taskforce or Technical Advisory Committee) to coordinate local and national response activities.

• Exclude laboratory errors or artefacts as the cause of positive test results by independent testing at a national SARS reference laboratory and at a WHO SARS International Reference and Verification Network laboratory (29). Testing at a WHO International SARS Reference and Verification Network laboratory will be especially important if the source of infection cannot be identified. Failure to identify source of transmission may be due to false positive test results, or a missed/occult source of transmission(environmental, animal or human), or a previously unrecognized source or route of transmission.

• Mobilize a multi-disciplinary team to investigate the transmission event. The composition of the team will depend on the likelihood of a human and/or environmental and/or animal source of transmission.

• As part of the investigation, ensure linkage of detailed clinical, laboratory and epidemiological data. Undertake studies of the molecular epidemiology, including comparisons of virus strains from the case and the likely source of transmission (environmental and/or animal sources). Laboratory investigations should also include quantitative virology wherever possible.

• Ensure that protocols and procedures for the containment, investigation, clinical and public health management of the case(s) and their contacts are implemented. This may require an inter-sectoral response involving several Ministries if the source of infection is an animal or environmental source or a breach in laboratory biocontainment.

• Initiate active case finding and serological studies for additional cases if warranted by the findings of the epidemiological investigation. Consider revision of national SARS surveillance case definitions to incorporate new epidemiological links (e.g. temporal and/or geographical criteria specific to the event).

• Enhance passive surveillance for SARS in areas reporting recent local transmission.


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• Review procedures for case investigation, community-based containment of SARS, infection control and laboratory biosafety, and other systems and structures for the prevention, containment and control of SARS-CoV transmission in light of the epidemiological data arising from the field investigation.

• Review the national risk assessment in light of the epidemiological investigation.

Outbreak affecting a laboratory

Phase 1 – Response: Countries/areas free of SARS

• If a case of SARS occurs in a diagnostic or research laboratory, the laboratory should be closed until an epidemiological and biosafety investigation is completed and appropriate measures, including decontamination, are implemented to eliminate the source of transmission. Depending on the physical layout of the laboratory, closure may be limited to specific laboratories or the entire facility in which the implicated laboratory(ies) is housed.

• Maintain awareness of global and regional SARS activity.

• Ensure that contingency plans are in progress if not already developed (Phase 0–1), especially if the national risk assessment determines that the country/area is at a higher risk of the introduction of SARS from local and/or international travel.


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5. Phase 2 – Confirmed human-to-human transmission

Phase 2, Level 1 – Chain(s) of transmission in one location

Criteria for Phase 2 Level 1

Chain(s) of transmission of SARS-CoV of two or more generations in one location.

The source case(s) resulting in chain(s) of human transmission are locally acquired from:

− an environmental source (laboratories working with live SARS-CoV or SARS-CoV-like viruses, or storing clinical specimens from humans or animals infected with such viruses) OR

− an animal source (inter-species transmission from exposure to wildlife or other animals that are the putative reservoirs of SARS-CoV-like viruses, their excretions and secretions).

All secondary cases occur among the known contacts of the source case(s).

There is no increase in the number of sporadic cases of SARS occurring locally or nationally.

Note for Phase 2, Levels 1 and 2: If the epidemiological and/or laboratory investigations provide compelling evidence that the source case(s) were a result of transmission in another country, there will be an automatic shift from Phase 2 to Phase 3 – International spread – until human chain(s) of transmission or a continuing source of SARS-CoV can be excluded in the putative source country.

Phase 2, Level 1 – Response: WHO The same as for Phase 1 AND also:

• Assist countries in mobilizing expertise to assist in the investigation of incidents leading to the emergence and transmission of SARS.

• Work closely with the country reporting SARS case(s) to monitor the extent of secondary transmission, the characteristics of the transmission events, the efficacy of control measures and the risk to other countries/areas.

• Issue multimedia updates describing the level of risk and control activities underway.

• Facilitate cross-border investigation and contact tracing should the source case(s) prove to have been infected in another country (international spread).


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Phase 2, Level 1 – Response: Countries/areas reporting SARS cases

The same as for Phase 1 AND also:

Outbreak affecting a health-care facility

Phase 2, Level 1 – Response: Countries/areas free of SARS The same as for Phase 1 AND also:

• Revise surveillance case definitions to include an epidemiological link to the country/area reporting recent local transmission for up to 28 days after the last reported case in the country/area (see the definition for the interruption of SARS in Section 8 - Phase 5 of the Framework).

• Expand active case finding in the area reporting SARS to exclude the possibility of missed chains of transmission or transmission beyond two generations of cases (i.e. beyond the source case and his/her immediate contacts).

• Consider lowering the threshold for SARS-CoV testing for ARI if warranted by the findings of the epidemiological investigation.

• Enhance passive surveillance for SARS in areas within the country presumed free of SARS.

• Establish a mechanism for cross-border notification and contact tracing.

• If the outbreak occurs in a health-care setting, consider closing the facility to new admissions pending completion of the epidemiological investigation. This will depend on the size of the facility and whether transmission of SARS can be interrupted with the facility open. If it must remain open to new admissions, remove all opportunities for exposure of susceptible patients, visitors and staff to infectious individuals, materials and environments through strict adherence to case isolation, infection control, fever monitoring and restrictions on access to the facility.

• Cohort exposed patients in an isolation facility or ward and place them on fever surveillance for at least10 days after the last exposure to the source case(s). If at the end of the observation period there is no evidence of SARS-CoV transmission, all patients in the cohort should be discharged home or to a rehabilitation facility at the same time if there is no other medical indication for their continued hospitalization.

• Place exposed staff on active twice daily fever surveillance. Exposed staff should either be cohorted to care for exposed patients only or redeployed to non-clinical duties for the entire period of observation depending on local circumstances ("work quarantine").

• Issue advice to all health-care workers and health facilities on transmission-based precautions, infection control and laboratory biosafety.

• Review the national preparedness plan in light of the global epidemiological situation. This may include establishing a mechanism for the cross-border notification of imported SARS cases.


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Phase 2, Level 2 – Chains of transmission in two or more locations but with no evidence of international spread

Criteria for Phase 2, Level 2

Chains of transmission of SARS-CoV of two or more generations occurring concurrently in two or more geographical areas but with no evidence of international spread.

The source case(s) resulting in chain(s) of human transmission are locally acquired from:

− an environmental source (laboratories working with live SARS-CoV or SARS-CoV-like viruses, or storing clinical specimens from humans or animals infected with such viruses) OR

− an animal source (inter-species transmission from exposure to wildlife or other animals that are the putative reservoirs of SARS-CoV-like viruses, their excretions and secretions) OR

− epidemiologically linked to an established chain of human transmission within the country.

Notes: The following factors/scenarios can be used to assess risk escalation from Phase 2, Level 1 to Phase 2, Level 2:

Phase 2, Level 2 – Response: WHO As for Phase 2 Level 1 AND also:

• Provide daily updates on the evolving epidemiological situation and any changes in the risk assessment.

• Publish global surveillance data.

• Consult regularly with the national governments in areas reporting recent local transmission of SARS through the WHO Country Office, Regional Office and/or directly from WHO HQ.

• Increase the frequency of communications with the global health community through the WHO working groups on SARS and through the communication mechanisms described in Section 2.

- The magnitude of the outbreak (cumulative total number of cases, the number of generations in each transmission tree, the rate of increase of new cases and the geographical spread).

- Evidence of ongoing transmission within health-care settings after control measures have been implemented.

- Identification of secondary cases that occur in individuals who are only identified as contacts of the source case(s) retrospectively.

- An increasing cumulative ratio of cases that are not linked to known outbreak locations or in whom the source of infection is unknown.

- An increasing number of sporadic SARS cases reported nationally which may indicate missed chains of human transmission.


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• If the updated risk assessment suggests that the likelihood of international spread is increasing, WHO will immediately convene an expert technical working group to advise on the need for travel-related measures. These measures may include travel advisories, screening at the borders (exit screening) and providing specific information to travellers.

• Consult with the travel industry as required on the risk of transmission to travellers, informed by the discussions of the expert technical working group.

Phase 2, Level 2 – Response: Countries/areas reporting SARS cases

As for Phase 2 Level 1 AND also:

Outbreak affecting a health-care facility

• Implement active case finding by lowering the threshold for SARS-CoV testing for ARI generally and febrile illnesses in high risk individuals.

• Run public campaigns to expedite the diagnosis and reporting of symptomatic persons to decrease the interval between onset of symptoms and case isolation.

• Raise public awareness of respiratory hygiene (hand washing, covering nose and mouth when coughing or sneezing) and appropriate health-seeking behaviour if unwell with a fever and/or cough illness.

• Assess the need to implement measures that increase social distance (e.g. cancellation of mass gatherings, closure of schools, theatres and public facilities, and requiring masks for all persons using public transport, working in restaurants, or entering hospitals, etc.).The effectiveness of these methods in unproven.

• Implement exit screening at air, land and sea borders and issue health advice in writing to departing passengers if recommended by the WHO expert technical working group convened to advise on additional travel related measures.

• If a safe and effective vaccine is available, consider ring vaccination of high-risk individuals.

• Close affected health-care facilities to new admissions. Restrict visitation to the affected facilities and implement universal temperature and absenteeism surveillance of staff.

• Notify patients discharged from the facility during the incubation period of the outbreak of the need for fever monitoring. Depending on the size of the facility and the number and location of affected wards, this may involve all discharged patients or only those considered at high risk of exposure. Public health authorities should actively follow up their outcomes.

• Trace patients discharged to aged care/long stay care facilities to ensure that they are isolated for the remainder of the incubation period (if applicable) before being admitted to general wards in the facility. Implement a fever surveillance system in these facilities.

• Assemble public health teams to conduct on-site investigations of all fever clusters/SARS alerts notified by aged/long stay care facilities and other residential facilities.

• Restrict the transfer of patients between health-care facilities wherever possible to reduce the risk of transmission between facilities.


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Phase 2, Level 2 – Response: Countries/areas free of SARS

As for Phase 2 Level 1 AND also:

• Monitor the epidemiological situation in the country(ies) reporting recent local transmission of SARS and communicate the risk to media and the public.

• Consider activation of the national preparedness plan based on the national risk assessment.

• Lower the threshold for considering SARS in the differential diagnosis and testing for patients with ARI and febrile illnesses from areas reporting recent local transmission. Ensure the appropriate use of PPE for triage staff and other health-care workers managing these patients.

• Provide information on SARS to incoming and departing passengers to encourage early presentation should they fall ill.

• If a safe and effective vaccine is available, identify first responders for vaccination and assess any contraindications to vaccination.


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6. Phase 3 – International spread of SARS


SARS Alerts may be reported concurrently from more than one country while awaiting laboratory confirmation of SARS.

Spread to one or more countries is the result of human chain(s) of transmission or a point source outbreak. The source country/area may be identified retrospectively during the case investigation.

Disease patterns indicate that serious morbidity and mortality is likely in at least one segment of the population.

Note: Depending on the amount of early warning, this phase may or may not have been preceded by the phases described above.

Phase 3 – Response: WHO As for Phase 2 Level 2 AND also:

• Issue a global health alert, identifying areas with recent local transmission of SARS and the assessed level of risk for each area.

• Consider issuing a travel advisory if indicated by the findings of the WHO expert technical working group convened to advise on additional travel related measures

• Further enhance monitoring and reporting of the evolving global epidemiology and impact of the virus. Revise case definitions as required.

• Mobilize teams to the field and facilitate other technical cooperation as required with logistic support.

• Actively work with countries reporting recent local transmission of SARS to minimize the risk of further international spread.

• Advocate for resources for countries reporting recent local transmission of SARS with limited resources through global partnerships.

• Actively determine regional capacity with respect to stockpiles of PPE, pharmaceuticals, other therapeutic modalities, laboratory supplies, etc. Identify and procure these supplies for countries if required.

• Work with national health authorities through WHO Regional and Country Offices as appropriate to encourage common activities among nations facing similar challenges from SARS and facilitate communication.

• Update guidance on case management, diagnosis, surveillance case definitions and public health measures as new knowledge emerges.

• Advocate for, and coordinate, global collaboration in public health and biomedical research and in


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evaluation. Facilitate the exchange of unpublished information needed for the public good through mechanisms agreed with the countries reporting SARS cases.

Phase 3 – Response: Countries/areas reporting SARS cases As for Phase 2 Level 2 AND also:

Phase 3 – Response: Countries/areas free of SARS As for Phase 2 Level 2 AND also:

• Review containment and control practices if there is evidence of continuing transmission in particular individuals or segments of the population.

• Communicate in a timely manner, new knowledge indicating changes in the epidemiology, clinical features, clinical response or efficacy of public health measures that indicate the need for new approaches to containment and control.

• Activate the national preparedness plan as rapidly as possible, updated to accommodate new knowledge on the specific characteristics of the circulating strain(s) of SARS-CoV/SARS-CoV-like virus(es).

• Revise local surveillance case definitions in accordance with updated guidance from WHO.

• Strengthen surveillance for SARS Alerts in acute care facilities.

• Report SARS Alerts to WHO within 24 hours of detection. Collaborate with WHO to obtain laboratory confirmation of individuals fulfilling clinical and epidemiological criteria for SARS if required.

• Ensure the availability of laboratory support for SARS diagnosis. Form links with WHO and/or a WHO SARS International Reference and Verification Network laboratory if not already established.

• If a safe and effective vaccine is available, vaccinate first responders. Depending on the efficacy, dosage schedule, availability and cost of the vaccine, consider vaccinating the population at highest risk of SARS morbidity and mortality.


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7. Phase 4 – Slowing down of the outbreak


A decrease in the number of new cases reported, significant interruption of chains of transmission and a net decrease in the number of countries reporting recent local transmission of SARS.

No new countries, or new areas within countries, report SARS cases.


• Continue to monitor and report on the evolving global epidemiology of the epidemic.

Phase 4 – Response: Countries/areas reporting SARS cases

As for Phase 3 AND also:

Phase 4 – Response: Countries/areas free of SARS As for Phase 3 AND also:

• Revise case definitions if required and remove countries/areas from the list of areas with recent local transmission.

• Work with countries that experienced sustained transmission to begin a step down process as their epidemic slows.

• Enhance surveillance and follow up of SARS cases and persons under investigation as the local epidemic wanes. The aim of surveillance activities in this phase is to demonstrate a sustained fall in the number of new cases once control measures are implemented and a sustained reduction in the proportion of cases in whom the source of exposure is unknown.

• Fully investigate persons with clinical evidence of SARS in whom the source of exposure is unknown to either confirm the diagnosis or confidently discard the case. The latter will require late convalescent phase serology.

• Increase laboratory testing as the epidemic wanes to detect diagnostic confusion with other causes of ARI.

• Maintain control measures to prevent the reintroduction of SARS in accordance with the national risk assessment while working with WHO to begin a step down process as the global epidemic slows.

• Monitor the global epidemiological situation to determine when to initiate step down procedures.


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8. Phase 5 – Global interruption of SARS-CoV transmission (epidemic halted)


Twenty-eight (28) days after the last reported case of SARS globally has been placed in isolation or died AND the source(s) and route(s) of transmission have all been identified and contained.

The last reported case would be one of the following:

− A "probable" or "confirmed" case of SARS OR

− A death from acute respiratory disease in:

1. an area with human chain(s) of SARS-CoV transmission where autopsy findings are consistent with the pathology of pneumonia or acute respiratory distress syndrome (ARDS) without an identifiable cause OR

2. a close contact of a "preliminary positive" or "confirmed", infectious case of SARS within the 10 days prior to the onset of symptoms or death in whom an autopsy was not done (verbal autopsy only) AND/OR in whom laboratory testing was not done or was incomplete.


• Declare the epidemic to be over 28 days after the last reported case of SARS globally has been placed in isolation or died AND the source(s) and routes(s) of transmission have all been identified and contained.

• Step down to Phase 0 after assessing of the risk of unrecognized SARS-CoV transmission in areas with sustained local transmission. A step down from a level of alert will be considered using the criteria listed below. When considering whether to initiate a step down, an assessment will be made of the following:

1. Evidence of satisfactory identification and containment of all source(s) and route(s) of transmission.

2. Assessment of the relative strength of acute medical and public health infrastructure in the areas that experienced sustained local transmission, especially their surveillance and response capacity. [National health systems have demonstrated their ability to detect, prevent and contain SARS cases].

3. The completeness and adequacy of health intelligence and its impact on the identification of cases. [The information provided to WHO is accurate and complete, and provides strong evidence that case ascertainment is complete].


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4. There is no evidence that SARS-CoV has become endemic in the human population of one or more countries/areas with sustained local transmission during the epidemic. Note: The extended period of vigilance for SARS arises from the lessons learnt during the 2002–2003 epidemic and is recommended to reduce the risk of new outbreaks arising from missed SARS infections (30,31) or incubation periods beyond 10 days (32–36). The second wave of SARS transmission in Canada was attributed to the inherent difficulties in diagnosing SARS when the clinical presentation is atypical and prematurely stepping down respiratory precautions in hospitals (30,31).

• Organize consultations and meetings to undertake the following: 1. Assess the impact of the epidemic. 2. Evaluate lessons learnt that will assist in responding to future outbreaks. 3. Establish criteria for endemicity if sporadic cases continue in some countries/areas after

interruption of epidemic spread of SARS-CoV. 4. Update the WHO SARS Risk Assessment and Preparedness Framework.

Phase 5 – Response: Countries/areas reporting SARS cases • Step down to Phase 0 following a national assessment of the risk of unrecognized SARS-CoV

transmission based on the WHO criteria above, unless SARS-CoV has become endemic in the human population.

Phase 5 – Response: Countries/areas free of SARS

• Step down to Phase 0 unless SARS-CoV has become endemic in the human population of one or more countries/areas with sustained local transmission during the epidemic or WHO issues a statement advising countries to continue at a heightened level of alert.


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