Virusphere: What doesn’t kill you makes you stronger

Today we can scarcely imagine the terror of living through a major epidemic of plague or smallpox sweeping through such a ‘virgin’ population. They would have been very quickly aware that a pestilence was among them, with panic-stricken populations in the grip of raging fever and, in case of smallpox, a virulent rash, which, when severe, caused the entire skin to boil with blisters and carried with it a horrific lethality, at its worst as high as 90 per cent. It must surely have seemed as if a pitiless demon had entered their world, intent on wiping out entire families, and even entire villages, towns and cities.

But smallpox was never a uniform death sentence. We cannot be certain of the actual levels of lethality of smallpox in various parts of the Americas, though we are informed that it was as high as 60 to 90 per cent in the worst-affected populations, falling to 30 to 35 per cent in some of the lesser-affected regions. This lower lethality was in fact similar with the calculated overall mortality of Variola major in concurrent Eurasian populations, suggesting that the virus had already become endemic in those regions. Meanwhile, even in the Americas, the Variola minor virus caused a much milder disease, with a mortality of about 1 per cent. It is somewhat ironic that smallpox, one of the deadliest plagues in history, was the first to be subdued by the use of a vaccine. Many readers will be familiar with the discovery of cowpox vaccine by the English physician, Edward Jenner, and this more than a century before the world even realised the existence of viruses.

In such less-enlightened times various therapies that we would now dismiss as ‘quack’ were touted as preventions or curatives for every frightening illness. In seventeenth-century England, for example, Dr Sydenham, an eminent physician in his day, treated patients in the throes of smallpox by allowing no fire in the room, leaving the windows permanently open, drawing the bedclothes no higher than the patient’s waist and administering ‘twelve bottles of small beer every twenty-four hours’. If nothing else, the beer would have dampened consciousness of the suffering – and perhaps the discomfort of the therapeutically induced hypothermia in winter. But it was famously known from ancient times that survivors of smallpox were immune to further infection. A hazardous treatment, involving inoculation of non-immune individuals with a scalpel wet with material from the ripe pustule of an infected patient, was variously employed in Africa, India and China long before Jenner introduced his vaccine.

History has it that Jenner overheard a dairymaid say, ‘I shall never have smallpox for I have had cowpox.’ Cowpox, a milder pox infection in cattle, was known as vaccinia, after the Latin, vacca,for cow. In 1796 Jenner conducted a now-famous experiment in which he inoculated an eight-year-old boy with pus from a vaccinia blister, obtained from a dairymaid with cowpox, and, having waited for the boy to develop immunity, subsequently tested this by inoculating him with smallpox. Thank goodness that the boy now proved to be immune. Although Jenner had rivals, who dismissed the importance of his discovery, the cowpox inoculation was soon taken up as a preventive measure against smallpox. We still refer to it today with the term Jenner coined for it: ‘vaccination’.

When I was a child, it was still mandatory to be vaccinated against smallpox. I still bear the scar, which is a pock-shaped irregular oval about half an inch in diameter, on the skin of my upper left arm. Today children are no longer vaccinated against smallpox because the disease was eradicated from the global human population by a ten-year international programme of smallpox vaccination, headed by the American physician, Donald Ainslie Henderson, who worked under the auspices of the World Health Organization. This was formally signed off with the confirmed eradication of the disease in 1979.

There can be no denying that the eradication of smallpox was an extraordinary achievement. Ironically, however, this very success makes our modern populations unduly susceptible to a malicious attack involving a potentially bioengineered smallpox virus that might be deliberately created to be as lethal as possible. New generations, who have never been vaccinated, would have no inbuilt protection to such a spreading lethal strain. This is why the smallpox virus is now included in the list of Category A bio-warfare agents. Following smallpox eradication, it was agreed by international treaty that samples of the smallpox virus should only be retained in two maximum security laboratories – one at the CDC in Atlanta, in the United States, and one at similar facilities in Moscow, in Russia. The plan was to allow some continuing research aimed at countering any attempt to use the virus for bio-warfare, whether through terrorism or through formal hostilities between nations. We must hope that, if the worst comes to the worst, the officially sanctioned research in this small number of biosafety laboratories will come to our rescue with a modern vaccine, which will need to be spread globally with more efficiency than we have ever seen with any previous vaccination programme.