FROM the Millennium Bug to the “flesh-eating” bug, scares are a regular feature of our public life. Few of these panics turn into real crises. In 2003, the national panic attack was over severe acute respiratory syndrome, or Sars. Now the big flap is over bird flu. Will the danger from flu turn out to be real? Or is this simply another outbreak of needless anxiety? Three years ago, this column was one of the first to argue that the Sars scare was vastly overblown. Sadly, however,available facts make it is very hard to be similarly sanguine over the menace now posed by avian flu.
It is quite conceivable that the present eruption of anxiety over flu will prove to have been over nothing. Unfortunately, the difficulty is that whether or not this threat becomes a dangerous reality is enormously uncertain. The key issue is whether the virulent strain of H5N1 avian flu that has now killed dozens of people from China to Turkey mutates so that it can be readily transmitted between humans, leading to a global pandemic. The problem is that no one can know whether this will happen.
What is certain is that there is a sufficiently grave risk that the H5N1 virus might mutate in this way that we need to confront it, and the potential consequences, with great seriousness. Flu viruses mutate readily, morphing into new strains as they spread and reproduce through processes that scientists call genetic drift and shift.
So it is entirely possible that H5N1 will evolve into the cause of a pandemic flu. Worryingly, this flu strain has already gone through a number of variants and each time seems to have become more deadly, tougher, more easily spread and capable of attacking more species.
This process points us to the second big unknowable in assessing the risk from flu — the question of just how virulent an evolved H5N1 might prove in a form that could be passed between human beings. When it first infected humans in Hong Kong in 1997, H5N1 killed 35 per cent of those who caught it, Laurie Garrett, of the US Council on Foreign Relations, notes.
By early 2003, a new “Z” strain of H5N1 killed 68 per cent of those infected. Yet in more recent cases, mortality dropped to 36 per cent. If that sounds like good news, it isn’t; Garrett notes that just this sort of pattern has been, historically, the prelude to pandemic.
Although no one can know how many a new flu pandemic might kill, historical precedents are scarcely reassuring.
In the New England Journal of Medicine, Michael Osterholm reports that there have been ten influenza pandemics over the past three centuries and, although some were more severe than others, the lethal potential is clear. The 1918 “Spanish flu” killed between 50 million and 100 million people. Moreover, Dr Osterholm points out that, although the 1918 outbreak is often seen as an anomaly in its severity, the pandemic of 1830 to 1832 was, in fact, equally virulent.
Some expert opinion argues that a strain of H5N1 capable of human-to-human transmission could be even more lethal than the 1918 flu. For one thing, no “H5” flu — the letters refer to the two protein types that appear as spikes on the virus’s surface — has ever been in this category, and so there would be no stock of acquired immunity in any country’s population to help to limit the impact. Nor do the huge advances in medical technology over the past century offer much comfort, given the long, six-month timescale needed to produce a vaccine and the limited production capacities presently available.
Against this background, sensible policymakers will examine worst-case scenarios. So, if the unthinkable happens, what might be the economic consequences? Although Sars proved far less dangerous to health than was feared three years ago, its economic effects are instructive, and ominous.
Sars infected only about 8,000 people worldwide, killing 775. Yet Hong Kong was tipped into recession. In Canada, where just 44 died, the economy also shrank.
Clearly, a flu pandemic would involve economic repercussion much greater in magnitude. International trade would be severely disrupted, leading to damaging shortages of goods and materials, while air travel would quickly grind to a halt.
Many industries, from much of retailing, to restaurants, pubs and cinemas, would see demand evaporate as people chose to confine themselves at home, away from the danger.
Economies’ supply potential would also be hit hard, as companies suffered acute staff shortages, and this, in turn, could ratchet up inflation, confronting central banks with a dilemma over how they should respond. Stock markets, inevitably, would tumble.
Putting numbers on these phenomena is extremely tricky, of course — not least since much would depend on the psychology of people’s reactions. However, the US Congressional Budget Office (CBO) has attempted to construct some meaningful scenarios. Based on a severe flu pandemic on the scale of 1918, it estimated the economic effects of an outbreak in which 90 million Americans, just under a third of the US population, became sick and two million of those died, a fatality rate just under 2.5 per cent.
On this basis, the CBO projects that a flu pandemic would cut US GDP by 4.7 per cent — a blow slightly harder than that inflicted by typical US recessions since the Second World War. In fact, the impact would be exceeded only by the US recession of the early 1980s, which cut American GDP by more than 7 per cent.
More comfortingly, the CBO also projects that a milder flu pandemic would probably not trigger recession and even could be hard to trace in economic data. Still, it is hard to imagine the numbers for a severe outbreak would look much better for the UK, based on a comparable scenario in which 20 million Britons were infected and 400,000 died. Indeed, the more densely populated, more trade-dependent Britain could be harder hit.
This is scary stuff. And there is little, of course, that we can do about it. What is apparent though, is that the Government, and others worldwide, have a clear duty to do all that can be done to put in place all conceivable measures to mitigate the effects if the worst ever does happen.
