SARS: initial lessons for bioterrorism preparedness

While not as lethal as smallpox or other major diseases, SARS demonstrated that emerging infectious diseases have the potential to have devastating effects - in terms of both the human and economic costs. Moreover, as David Heymann of the World Health Organisation (WHO) says, SARS "is a difficult disease that produces many surprises and setbacks".

At the time of writing, it appears that the global outbreak of SARS has finally been brought under control. This previously unknown, highly contagious and lethal disease, with a mortality rate of around 10%, infected over 8,000 and killed over 800 people. SARS demonstrated that recent preparations for biological agent attack had improved the capability of public health to respond to disease outbreaks that are not intentional in nature. In the US, improved co-ordination and communication between the medical communities and local, state, and federal organisations resulted in the rapid identification of individuals infected, limited the total number of cases and prevented the disease from becoming a significant problem.

While the limited number of cases in the US made the task of preventing the spread of SARS easier, this experience was not the norm in the countries with a significantly higher number of cases (China/Hong Kong, Singapore, Taiwan and Canada). For various reasons, all of these countries experienced significant difficulties in containing the disease. In this respect, SARS provides a unique opportunity for detailed research of the response (both positive and negative aspects) to an outbreak of a highly contagious disease that could benefit public health and continuing bioterrorism preparedness efforts.

With this broader goal in mind, the purpose of this article is twofold: first, to identify some of the positive aspects of the response to SARS in comparison with the anthrax attacks in the US in 2001; and second, to extrapolate some initial lessons on which aspects of bioterrorism preparedness efforts might be re-examined in the light of SARS. In particular, the prominent role of quarantine in the SARS outbreak deserves specific examination. Although quarantine has been highlighted as a significant issue in numerous bioterrorism exercises, it is a subject that has received far less attention than it deserves.

As SARS finally appears to be contained, efforts at stopping the disease have been impressive. In contrast to the disjointed and unco-ordinated response to the anthrax attacks in the Washington, DC region in 2001, several aspects of the response to SARS were notably positive.

Perhaps most impressive was the level of co-operation that was eventually achieved among international organisations, nations, and communities. Such co-operation was instrumental in dealing with the disease. Although the Chinese government deserves criticism for the substantial delay in admitting the severity of the outbreak, its decision to confront the problem and work in conjunction with the WHO was crucial to containing the disease. Another effective measure was the use of travel advisories and the rapid enactment of screening measures at points of entry (in particular airports and seaports). Such measures allowed individuals who were either infected with or exposed to SARS to be identified and contained if necessary.

In contrast to the rampant speculation by the media during the anthrax attacks of 2001, the SARS outbreak was generally handled in a more rational fashion. Public officials, perhaps having learned from the public relations fiasco in 2001, appear to have used the media effectively to disseminate information on the nature of the disease in a generally accurate and timely fashion as well as on the required precautions and countermeasures. Finally, the use of traditional public health measures, particularly isolation and quarantine, were effective in limiting the spread of the disease.

Despite these positive aspects of the response, SARS and the response to it should raise some concerns with regard to bioterrorism preparedness efforts that have been undertaken over the past 18 months.

In the US, instead of pursuing a full-spectrum approach to preparedness, the overall strategy has essentially come to rest on two techniques to be employed in the event of a biological agent attack: mass vaccination and mass distribution of pharmaceuticals.

This approach appears to have been adopted because the biological agents regarded as the primary threats - anthrax and smallpox - can likely be effectively countered using these techniques.1 Unfortunately, reliance on this strategy rests on the assumption that a treatment (a vaccine or an effective drug) is available, which was lacking in the case of SARS.

How to respond to outbreaks (naturally occurring or not) for which there exists no vaccine or effective treatment will require more comprehensive planning, along with consideration of measures such as quarantine (both voluntary and involuntary) that were not seriously examined prior to the appearance of SARS. A recent article in the Washington Post on SARS preparedness noted that the Department of Health and Human Services has been working with the multiple jurisdictions in the national capital region to develop a response plan (including quarantine) for a massive SARS outbreak.2

While it is certainly not a new phenomenon, poor information-sharing contributed to the spread of the disease in several countries (especially during the initial stages of the outbreak in China). Infection control and surge capacity were also issues, due to the highly contagious nature of the disease and a long incubation period of about 10 days.

Heathcare workers were very susceptible to infection, and there were numerous cases of infected hospital staff members spreading the disease. It also appears that hospital to hospital contamination was a significant problem as well. By mid-April in Singapore alone, SARS had spread to five of the six major hospitals in the country. In Canada at least five medical facilities were contaminated as a result of patient transfers from a central hospital, resulting in the requirement to quarantine of over 5,000 people.3 If SARS had the fatality rate of smallpox, the ability of the healthcare systems to handle the crisis might have been overwhelmed.

The Chinese experience with SARS should be regarded with caution, as its experience may not be entirely applicable to other countries, but the subject of panic nonetheless deserves attention for future incident planning. Panic and the attendant population flight presented significant problems in Beijing once the extent of the disease became known.

The implication for future disease outbreaks is that a disease more lethal than SARS could result in widespread panic in the affected society. In the case of Beijing, it should be noted that panic began to spread and people began to take flight once public officials admitted the true extent of the outbreak. As was the case with the anthrax attacks, once a 'credibility gap' emerged, it was increasingly difficult to convince people to trust the information being disseminated.

The SARS outbreak was particularly significant in that quarantine was employed as a important and effective tool in preventing the spread of the disease. This procedure was implemented in almost every nation affected by SARS, and thousands of people were quarantined worldwide. While quarantine is by no means a new public health tool, it is a subject of controversy, particularly because of its potential infringement on civil liberties. At its core, the use of quarantine requires one to ask at what point the 'greater good' for society overrides individual liberties. In the case of SARS, the outbreak witnessed the use of both voluntary and involuntary quarantine.

The difficulty of enforcing quarantine was demonstrated in China, where officials threatened possible execution as an enforcement measure.4 In Canada, government officials in early April had to go to court to obtain isolation orders against seven individuals who refused to comply with the voluntary isolation.5 Establishing the 'rules of engagement', particularly for involuntary quarantine, remains a difficult issue. When will quarantine enforcement require the use of deadly force? Should a disease more virulent than SARS appear, this question will require an answer.

For quarantine to be used effectively, laws must be enacted that provide the power of enforcement. Even since the recognition of the potential threat posed by biological agent attack, few states in the US have revised their quarantine laws, some of which are more than 100 years old. The potential of SARS-like diseases that are highly contagious in nature should prompt a re-examination of national and local quarantine statutes.

Perhaps one of the most interesting aspects of quarantine and SARS that may be useful for future disease outbreaks was the utilisation of information technology. In Singapore, webcams were installed in the homes of quarantined individuals. Telephone calls were made at random times, and individuals were required to turn on the camera to prove they were still in their homes. "An electronic wrist band would be slapped on offenders, designed to send a signal if anyone tried to leave their home."6

While the use of such technologies will not provide a panacea for quarantine enforcement, the employment of such tools can improve response capabilities. Further research into this area is clearly necessary.

Although SARS appears to have been vanquished, at least for the time being, the difficulties encountered in containing the disease should not be ignored or forgotten. The SARS outbreak offers valuable and varied lessons for both decision-makers and the public health/ bioterrorism preparedness communities. Hopefully such lessons will be learned and not simply 'observed'.

Benjamin Tuck specialises in homeland security and bioterrorism issues at L-3 Communications Analytics Corporation. He is currently on a leave of absence serving with the US Army in support of the war on terrorism

NOTES

1 In the case of smallpox, however, the reliance on mass vaccination only became possible once sufficient quantities of vaccine were discovered.

2 Washington Post, 7 July 2003.

3 New York Times, 29 May 2003.

4 www.chron.com/cs/CDA/ssistory.mpl/special/ sars/1912142, 15 May 2003.

5 CBC news, "Court Action Taken to Enforce SARS Quarantine", 4 April 2003.

6 MSNBC, "Webcams enforce SARS Quarantine", 10 April 2003.