Face masks, deserted airports, quarantines, school closures, cancelled conferences and holidays - has it all been a hysterical over-reaction?
No: it has been worse. It has been a grave under-reaction.

Daniel Haydon and Olivia Judson
Financial Times May 8 2003

Daniel Haydon is an epidemiologist at the University of Guelph, Ontario; Olivia Judson is an evolutionary biologist at Imperial College, London

The unavoidable conclusion from the outbreak of severe acute respiratory syndrome (Sars) is that the world is not ready to cope with outbreaks of disease that pass easily from one person to another, especially when, as with Sars, there is limited treatment and no vaccine.

How easy it is to control a particular infectious disease depends on a number of variables: how the disease is transmitted, how hard it is to catch, whether apparently healthy individuals can spread infection and whether the disease organism has a "reservoir" in another species. But the most important factor is time. The faster effective control measures are put in place, the fewer individuals will have been exposed and the easier it will be to prevent the spread of infection. This sounds so obvious as to be scarcely worth mentioning. Yet it is a lesson we seem unable to learn.

In these days of high-speed travel, delays of even a few hours can be disastrous; in the time it takes to contact the relevant authorities and schedule a meeting to discuss control measures the disease can take hold.

The Chinese authorities first failed to report the existence of Sars and then tried to hide the extent of infection. This obfuscation reduced the World Health Organisation's ability to respond. Although the WHO responded with commendable alacrity once it was clear there was a problem, weeks had already been lost, tipping the balance in favour of the virus. In contrast, the Vietnamese government responded instantly to the first cases of Sars; as a consequence, the total number of infections was small and the country was first to be declared rid of the disease.

The means of controlling new communicable diseases are necessarily crude. If there are few cases, it may be enough to isolate everyone known to be infected and everyone they are known to have met. With many cases, however, tracing each contact is impossible, and the only method of control is mass quarantines, which are difficult to enforce. Historically, quarantines have led to violence, riots and attempted escapes - exactly what the Chinese government now faces.

So, how can we do better in future? First, better systems for reporting new diseases are clearly necessary.

Second, we need procedures for relaying details of symptoms to frontline healthcare workers so that new cases can be recognised promptly.

Third, we need to develop ways to put effective and enforceable large-scale quarantines into place quickly. Public education is essential here: travelling when sick with a serious, communicable disease is, at best, irresponsible, and at worst, potentially genocidal.

Fourth, we need to develop an internationally agreed series of automatic triggers for the instigation of control procedures such as culls (for animals) and quarantines and show that these can be justifiable and imperative. Such measures may seem draconian and if successful, will often seem to have been an over-reaction, but the alternative is worse.

Fifth, we need fast protocols for the development of mobile and rapid infection test kits. Such tests are technologically within our grasp and are crucial for effective, manageable, justifiable quarantine procedures.

Finally, the study of new infectious disease agents and, especially, their reservoirs should be an urgent priority.

For a bug, expanding your range of hosts to include one of the most numerous large mammals on the planet is the evolutionary equivalent of winning the lottery. So far we have, in some respects, been lucky. HIV is transmitted through known behaviour; people sick with Ebola are only briefly contagious; Sars is relatively uninfectious.

But sooner or later, we will be confronted with a truly awesome bug. It will start, as Sars did, with reports of strange illnesses in a remote corner of the world. And this is when a well-oiled global response - one understood and supported by government, business, and the population at large - should kick in. Sars is a dress rehearsal.

When the curtain goes up for the big one, there will not be room for error.

Full text

FT about Sars

Centers for Disease Control and Prevention (CDC)