SARS: the True Story - programme summary

Severe Acute Respiratory Syndrome didn't even have its name in February 2003, when it struck its first known victim, Johnny Cheng, in Hanoi, Vietnam. Within days, an international effort led by the World Health Organization (WHO) had massed scientific expertise to fight the mystery illness and avert the nightmare scenario of an uncontrollable pandemic sweeping the globe.

"Unless you know what you're looking for, you've no tools to find it"

Mike Leahy, virologist

Amid attempts to quarantine high risk groups of people, it seemed only fear could spread more rapidly than the disease itself. Nothing was known about the condition - where it had come from, how it was passed on, how to spot it, contain it or treat it. The infection was described merely as 'flu-like'. But if this was a type of influenza, it was one that killed up to 15% of its sufferers.

The doctor treating Mr Cheng, who first contacted the WHO about the unusual symptoms, was one of six medics to die of SARS at the hospital. But the alarm had been raised and the Organization began to pull together a response. Colossal effort by scientists around the world - and unprecented co-operation - followed. Meanwhile, the media made much of the risk posed by and to international travel, and watched financial markets respond in gloomy fashion.

Global concern

The SARS virus first emerged in the Chinese province of Guangdong. There had been rumours of a unusual and virulent pneumonia-like illness in the region, but nothing was certain. The Chinese authorities had begun work - ruling out diseases such as ebola and other haemorraghic fevers - but they had no effective medical response to the condition. And given its appearance in Vietnam, containing the unknown infection was already an uphill struggle.

In Geneva, the WHO rapidly accepted the need for global action. Working from a never-used plan drawn up to deal with a 'flu pandemic, it started marshalling forces to identify the contagious agent and develop a treatment response.

The Organization's 'flu specialist is Dr Klaus Stohr. Charged with finding out what the virus was, he too began crossing off what it was not. To his alarm, he realised they could not identify it because it was brand new.

"We were dealing with something unknown... incredibly scary"

Julie Hall, World Health Organization

Unprecedented action

Two weeks since the Vietnam case, people were falling victim across Asia - and then on 13 March Toronto, Canada, went on SARS alert after a suspected fatality. If anyone thought the mystery disease was a regional problem, this was a wake-up call. On 15 March, the WHO responded with an unprecedented world wide alert.

Naming it for the first time as Severe Acute Respiratory Syndrome, it issued guidance for medics: the symptoms to look for and how best to respond. Its treatment advice was based on isolating suspected carriers. While Hong Kong remained the epicentre of the outbreak, the global alert brought to light suspected cases in previously unaffected countries, from Thailand to Germany.

The WHO next sought to unite laboratories the world over to study the virus agent. It persuaded them to put aside their professional rivalries and join forces to combat the mysterious killer.

Tracking the virus

In Hong Kong, Thomas Tsang was part of a team tracking the history of SARS' spread, looking for the first traceable sufferer, the index case. Unusually, he found him: a Chinese doctor called Liu Jianlun. The 9th floor of the Metropole Hotel in Hong Kong had recently been home to Liu, as well as - at the same time - Johnny Cheng and the woman known to have carried SARS to Toronto. It was a hint that close contact was essential, that the virus was less durable and contagious than, for instance, influenza. Less good news, of course, was that a major hotel in a transport hub like Hong Kong was the perfect place from which SARS could begin to travel the globe.

"Traditionally, coronavirus causes sniffles. This has turned nasty"

Mike Leahy

Species jump

The hunt for what SARS was bore fruit on 24 March. Working from samples obtained in Hong Kong, a process of random matching showed that SARS was a new form of a coronavirus, a pathogen known to affect humans, but not a global killer.

The Chinese province of Guangdong is largely agricultural and many people live in close proximity to animals. Ordinarily, animal viruses don't infect human cells, as their surface proteins do not match. But mutations can and do occur. With so many birds and mammals in such close contact with humans, the chance of a species jump increase. And when a jump occurs, the disease's behaviour can change markedly too.

The new information certainly helped slow the rising rate of SARS cases. But if the WHO thought the worst was past, China was about to destroy any sense of satisfaction. At a time when strict containment of all known contacts was vital, the health ministry there announced the outbreak had actually begun five months earlier and that they had far more than 40 cases; they had nearly 400. With First World cities like Toronto still struggling to contain their outbreaks, it seemed fears of a long-lasting global threat were well-founded.

A battle that can be won

Calm was restored almost by accident. The WHO's world wide alert worked. Close examination of arriving travellers, hospital staff and other groups led to effective quarantining of possible carriers. Vietnam - the poorest country to experience an outbreak - was the first to be declared SARS-free.

There are no specific drugs to combat SARS (Sufferers have been given steroids in an attempt to help their lungs cope with the infection.) but the story is a positive one. By comparison with the 5,000 that 'flu kills annually in Britain, the 750 victims of SARS across two continents seems slight. DNA analysis of the virus has revealed its genetic code in record time. The coalition of scientists brought together by the WHO has discovered that SARS is far from an unstoppable monster. On the contrary, it has barely mutated in the months since its emergence, making finding a drug treatment or vaccine relatively easy.