Scientists have in recent months been monitoring the emergence of a new coronavirus — a variant of the respiratory virus that causes the common cold — which so far appears to have infected 15 patients and caused nine deaths across the world.
To understand why health organizations are so exercised about this development, it is worth revisiting the events of the SARS outbreak of 2003 — an epidemic also caused by a coronavirus. Ten years ago, that epidemic swept across the world, killing 775 people. Yet if it had not been for the quietly heroic efforts of public health officials, and those in frontline hospitals, the toll would have been far higher.
SARS first came to light in Vietnam in February 2003 at the French Hospital of Hanoi, when Johnny Chen, a US businessman of Chinese extraction, was admitted with a strange febrile illness. He rapidly became critically unwell and Carlo Urbani, an infectious diseases physician working for the WHO, was asked to go to Hanoi to investigate. Within days, many of the healthcare workers at the hospital had also become ill. Urbani quickly realized that this was a disease of dangerous character: something highly infectious and lethal. Of the infected hospital staff, several would be admitted to intensive care and two — an anesthetist and a nurse who had attended Chen in the early days of his admission — would go on to die (as did Chen himself).
Urbani was tireless in his efforts to support the team at the hospital. He helped reinforce basic, but important, infection control measures such as hand washing, gloves and masks. He and his colleagues liaised with the Vietnamese authorities and summoned further assistance from the WHO and other international organizations. Tragically, having spent two weeks in the presence of SARS, and being instrumental in measures that proved essential in identifying and later containing the disease, Urbani himself would fall victim to the virus and die in an intensive care unit only weeks after leaving Vietnam.
The brunt of the 2003 SARS outbreak was borne by frontline medical staff. From the outset, healthcare workers appeared to be most at risk. There was good reason to fear SARS: The deaths caused by the virus were not from simple exhaustion in frail individuals, rather, SARS was able to infect and kill people in otherwise robust health. In the early days of the outbreak, the disease seemed to be terrifyingly aggressive, causing hearts, lungs and kidneys to fail rapidly. There were moments when the ferocity of the disease made some clinicians wonder if anything would stand in its way.
Having witnessed first-hand what the virus could do and knowing that other healthcare workers had already succumbed to the disease, many hospital staff took the brave step of quarantining themselves from their friends and family. The teams also continued to turn up for work, day in and day out, despite the risks that SARS presented to them.
The battle against SARS was fought on many fronts: Laboratory scientists identified the organism, public health officials tracked its origins to China’s southern provinces and, through a remarkable investigative effort, identified Johnny Chen’s principal contacts. Those working in intensive care held the line against what initially appeared to be impossible odds, providing a much-needed bulwark against the mystery illness.
The policy of containment and travel restriction advocated by the WHO ultimately proved successful. By the summer of 2003, the disease had all but run its course. It transpired that, luckily, the virus was maximally infective only when patients were at their most unwell and usually already in hospital. This explained the huge risk to hospital staff, but the relatively low rate of infection in the wider community. Deadly, but unable to spread efficiently, and with SARS victims largely contained within hospitals, the virus burned itself out in intensive care beds across the globe.
It is for this reason that the newly reported coronavirus, principally observed in the Middle East, is of such interest. Laboratory investigations have been successful in characterizing the nature of the virus, but the true lethality of the disease and the efficiency with which it might spread can only be determined by carefully monitoring its behavior.
For epidemiologists tracking these viruses and their rapidly evolving genomes, this is an onerous task: watching and waiting, monitoring fatalities and clusters of infection, and trying to determine the right time to act.
The coronavirus now circulating in the Middle East has some worrying features: It is capable of causing destructive pneumonias and, most recently, appears to have acquired the ability to spread from person to person. Nevertheless, the risk to the general public remains low. Thankfully, the cocktail of properties required to produce a dangerous pandemic has not yet manifested. It remains then for disease surveillance officials to keep up their watch. For them, knowing the right time to put public health measures in place is a difficult balancing act. However, we should be thankful for their vigilance.
This month marks 10 years since the identification of SARS, the announcement of the WHO’s global health alert and the death of Urbani. It is an anniversary that deserves some recognition. These events set the template by which future outbreaks might be successfully contained. The experience of the 2003 SARS outbreak taught us that, when dealing with airborne viruses with pandemic potential, prevention is always better than cure.