WHO Global Conference on Severe Acute Respiratory Syndrome (SARS)
Where do we go from here?
On 17–18 June 2003, the World Health Organization sponsored a global conference on SARS: where do we go from here? in Kuala Lumpur, Malaysia. Over 900 participants traveled from 441 countries to present first-hand clinical, laboratory and epidemiological experiences and exchange views on what works best to contain SARS.
Scientific experts reviewed accumulated knowledge to date, extracted practical lessons, and identified key priorities for the future. Presentations were organized to address three overarching questions:
- Can SARS be eradicated?
- Are current control measures effective?
- Are current alert and response systems appropriately robust?
The first day began with presentations on the history of the epidemic, global and regional responses coordinated by WHO through its headquarters in Geneva and its Regional Office for the Western Pacific in Manila, and national responses in the People’s Republic of China, Hong Kong Special Administrative Region of China, Singapore, Viet Nam, Canada, and the United States of America. Nine presentations reviewed the state-of-the-art in scientific knowledge. Experts with extensive personal experience described the etiology of SARS, discussed clinical diagnosis and management, reviewed the status of diagnostic tests, and considered what is known about the epidemiology of the disease. Efforts to develop a vaccine were also summarized. Other papers discussed the role of animals in the emergence of SARS and the possible existence of an animal reservoir, explored the part played by environmental factors in the transmission cycle, assessed the psychological impact of SARS, and summarized the challenging problem of risk communication.
On the second day, breakout groups met to seek answers to the three overarching questions and to formulate recommendations for future action in line with these answers.
Global, regional, and national responses
Presentations on the global and regional responses to the outbreak provided an account of the swift and sweeping measures that began shortly after SARS was recognized as a threat to international public health. Global alerts, issued by WHO and amplified by the media, resulted in a high level of vigilance that worked to promote the rapid detection and isolation of cases imported into new areas. To support the earliest and most severely affected areas, WHO, its Regional Office for the Western Pacific, and the WHO Global Outbreak Alert and Response Network (GOARN) provided direct technical support, including expert staff, to assist in epidemiological investigations and containment operations.
To accelerate research about a new and poorly understood disease, WHO established three virtual networks of virologists, clinicians, and epidemiologists, who shared experiences and findings on secure web sites and during daily teleconferences. Within a month, the causative agent was conclusively identified. Case definitions, practical guidelines, and recommended control measures, published on the WHO web site, evolved as new knowledge about the disease emerged. A high level of awareness and political commitment, around the clock research, open sharing of experiences and findings, and rapid communication of information contributed to the refinement of control strategies and their effective implementation.
From the outset, the WHO objective had been to halt further international spread and prevent the new disease from establishing endemicity. Reports of national experiences indicated that such a goal was feasible. Application of classic epidemiological measures, including patient isolation, infection control, contact tracing, proper management of contacts, and restrictions on travel, had proved effective in all affected countries, despite the diversity of health systems involved and differences in the severity and epidemiological characteristics of the outbreaks. Country reports also illustrated the rapid improvements in health systems, including many innovations, that could be achieved when an infectious disease became the focus of considerable public and political concern.
Can SARS be eradicated?
The breakout groups concluded that, while it was too early to determine whether SARS could be eradicated, several significant problems stood in the way of reaching such a goal. The experts agreed that current chains of person-to-person transmission could probably be interrupted, provided no reservoir of asymptomatic carriers exists, chronic infection does not occur, and difficult new areas, such as Africa, do not experience cases. In particular, the existence of an animal reservoir of the SARS coronavirus, as suggested by some studies, would make eradication extremely difficult to achieve. Faecal shedding of virus by infected persons and apparent virus stability in the environment could pose additional barriers to eradication, although these were not considered major modes of transmission in the current outbreak.
Priorities identified by the group focused on the need for more knowledge about the epidemiology of infection and transmission, and more research on the virus. Specific issues requiring further research were judged to include the significance of “super spreading events”, the host range of animals that may carry the virus, factors leading to emergence, the role of environmental sources, and the effectiveness of different interventions in controlling the epidemic. Additional priorities identified included standardization of diagnostic assays and reagents, development of a reliable point-of-care diagnostic test for use early in illness, improvement of procedures for the safe shipping of specimens, and development of animal models to improve understanding of pathogenesis and the clinical course of disease, and for use in vaccine development and the testing of antiviral drugs.
Are current control measures effective?
The experts agreed that currently recommended measures to prevent transmission in health care settings were theoretically highly effective, but required proper infrastructure, training, and consistent application to ensure efficacy. Such measures were also extremely resource intensive, socially disruptive, and difficult to sustain over time. Infection control capacity and practices in many health care settings needed improvement. A minimum global level of safe practice (standard precautions supplemented by risk-based precautions) should be established. Studies were needed to determine optimal protective measures, such as the type of mask, and when these measures should be used. In addition, appropriate protective measures, including isolation facilities and masks fit-tested for individual workers, needed to be more widely available.
Measures to control community transmission (outside of health care settings) and prevent international spread required further evaluation to determine their effectiveness. Such measures included public information and education campaigns to encourage prompt reporting of symptoms, hotlines to report fever, establishment of fever clinics to relieve pressure on emergency rooms, temperature screening in public places, recommendations to travelers, and entry and exit screening at borders using questionnaires and temperature checks. The effectiveness of contact tracing and voluntary isolation or quarantine of contacts had been amply demonstrated.
The experts suggested that control measures in the community would have the greatest impact if focused on links between health care settings and the wider community, with contact tracing prioritized according to the nature of exposure. However, further evaluation was needed before firm conclusions could be reached. Home or institutional quarantines, when included in control strategies, should be complemented by financial and psychosocial support, and should further ensure that the daily needs of affected individuals were met. Stigmatization of affected individuals and groups, fuelled by a climate of fear and inadequate objective information, was identified as an especially important issue. Some participants held the view that visible measures to control community and international spread were important in restoring public and business confidence and as deterrents, regardless of their efficiency in detecting SARS cases.
Are current alert and response systems appropriately robust?
As the experts noted, mounting success in the containment of SARS has demonstrated the adequacy of current alert and response systems. However, the demands of combating SARS have stretched these systems to their limits. Control interventions – however successful – could not be sustained over time. Improved surveillance would require preparation of a sensitive “alert” case definition in areas at greatest risk for recurrence, development of a point-of-care diagnostic test to identify patients with SARS infection during periods of high incidence of other respiratory illnesses, strengthening of laboratory diagnostic capacity and laboratory-based surveillance, and development of integrated information tools that allow real-time analysis of clinical, epidemiological, and laboratory data.
Priorities for improving response included development of contingency plans, better mechanisms for coordination, much greater surge capacity at global, regional, and national levels, and strengthened laboratory capacity and systems for information technology. Revision of the International Health Regulations, currently under way, should further strengthen capacity to contain emerging infectious diseases.
Communication of information to the general public and the media was singled out as another component of an effective response. Information should be communicated in a transparent, accurate and timely manner. SARS had demonstrated the need for better risk communication as a component of outbreak control and a strategy for reducing the health, economic, and psychosocial impact of major infectious disease events.
SARS dramatically illustrated the wide-ranging impact that a new disease can have in a closely interconnected and highly mobile world. It also underscored the importance of a coordinated global response characterized by close collaboration and open sharing of data and experiences. WHO’s capacity to lead and coordinate such responses had been given added authority during the 56th World Health Assembly in May, 2003. In response to the SARS outbreak, delegates unanimously adopted a resolution authorizing WHO to act on information arising from sources other than official government notifications, and to conduct on-the-spot investigations to ensure that control measures within an affected country were sufficient to contain the disease protect against its international spread. This strengthened capacity should facilitate all ongoing and future efforts to minimize the damage caused by infectious disease events of international concern and, if possible, to contain new diseases before they have an opportunity to establish endemicity.
Research priorities identified by participants will need to be pursued, especially since a seasonal recurrence of SARS cannot be ruled out. Apart from work on the development of a vaccine and effective treatments, urgent needs were judged to include a reliable point-of-care diagnostic test, a revised case definition, better knowledge about the efficacy of interventions, and more research on potential animal reservoirs. Predications concerning the possible recurrence of SARS will not be possible pending better understanding of the conditions under which this new disease initially emerged.
From the global perspective, the SARS epidemic demonstrated the importance of a worldwide surveillance and response capacity to address emerging microbial threats through timely reporting, rapid communication, and evidence-based action. Many participants stressed the importance of international collaboration, coordinated by WHO, in advancing the research agenda, and the need for partnerships among clinical, laboratory, public health, and veterinary communities.
From the national perspective, lessons learned included the need for strong political leadership at the highest levels to mobilize entire societies, speed of action, improved coordination between national and district levels in countries with federal systems, increased investment in public health, and updated legislation pertaining to surveillance, isolation, and quarantine measures. Participants also noted the need for improved infection control in health care and long-term care facilities, and for screening measures at borders to minimize the risk of imported cases and at international airports to minimize the risk of exported cases.
Although SARS took advantage of conditions in a globalized society to spread rapidly and cause wide-ranging disruption, control efforts benefited greatly from the world’s interconnectedness. Communication technologies were used effectively – from web alerts to daily electronic reporting of cases to support for “virtual” laboratories – to amplify available resources and accelerate progress in both the generation and dissemination of knowledge.
1 Australia, Bangladesh, Belgium, Brazil, Brunei Darussalam, Canada, Chile, China (People's Republic of), Denmark, Egypt, Finland, France, Germany, Ghana, Greece, Guatemala, India, Indonesia, Israel, Italy, Japan, Kenya, Malaysia, Mongolia, Netherlands, Norway, New Caledonia, New Zealand, Nicaragua, Pakistan, Philippines, Republic of Korea, Saudi Arabia, Singapore, South Africa, Spain, Switzerland, Syria, Thailand, Trinidad and Tobago, United Kingdom of Great Britain and Northern Ireland, United States of America, Viet Nam, Zimbabwe