Epidemics in Western Society Since 1600

HIST 234 - Lecture 7 - Smallpox (II): Jenner, Vaccination, and Eradication

Chapter 1. Smallpox in Europe [00:00:00]

Professor Frank Snowden: Now that we've discussed smallpox and its impact on the human body — its symptomatology — this morning I want to concentrate instead on the impact on history, and I want to concentrate on three aspects in particular. The first part would be to look at its impact in Europe. The second, and much more dramatic story, is the impact that you're reading about in Elizabeth Fenn, which is what happened with smallpox in the New World, and also in Australia and New Zealand. The third task for the morning is to come to the very different story, which is smallpox and the development of a public health strategy; in this case, the development of the strategy of vaccine.

So, those are the three topics I'd like to deal with this morning. And, so, let's begin with the impact of smallpox in Europe. Smallpox has a legend about it. The legend, it goes like this. That it was brought back to Europe from the Middle East by returning Crusaders in the eleventh and twelfth centuries. As you know, the Crusades lasted from 1095 to 1291, and those are said to be, this time of armies in movement and transit, to be the means of transmitting smallpox back to Western Europe.

There's no reason for us to accept the truth of that legend as accurate. But there is something interesting about it. First, that there's some support, which is that Saint Nicaise, who was a Crusader of the Order of Saint John, he had an unhappy experience in the Middle East. He was captured and beheaded. But thereafter he became the patron saint of smallpox sufferers. A cult of Saint Nicaise — he's from Reims, in particular — spread across the continent, and churches were devoted to him, and there were representations of this saint in stained glass widows, in effigies, and statues like this. This is Saint Nicaise at Reims Cathedral, Saint Nicaise and an angel.

There isn't any hard evidence that smallpox did return with the Crusaders; although, we all know that warfare is a time that favors the spread of infectious diseases, and it's probably true that smallpox had already been present in Europe for centuries. But there's something about this date, which is that what it tells us is not when smallpox actually began, but when it first began to attract attention. In any case, we know too that smallpox, although it was present in Europe during the Crusades, the conditions at that time led to its beginning to have a more important impact, that reached its highpoint in the late-seventeenth and then throughout the eighteenth century. And that had to do with preconditions that enabled it to flourish, preconditions associated with industrial development, the commercialization of agriculture, and rapid, unplanned urbanization.

In the eighteenth century, smallpox had clearly replaced plague as the greatest and most feared killer of its time. Now, in its history, the fact that a sufferer — and we mentioned this last time — who recovered possessed a robust, lifelong immunity to this disease was important. No one was naturally infected twice with smallpox. So, a typical pattern emerged in the cities of Europe, and that was that smallpox became an ever-present disease that most people who survived childhood had suffered. The adult population therefore possessed what we might call an extensive herd immunity to smallpox as a disease.

So, it became an endemic disease of childhood. But at intervals, perhaps every generation or so, smallpox would erupt as a major epidemic among the general population. A couple of factors came into play, to reinforce this pattern. Obviously not every child contracted the disease, and so over time there'd be a slow accumulation of non-immune, susceptible adults who could fall ill of the disease. It was also true that European cities in the early modern era were so unhealthy that they sustained or expanded their population, not by growth from within, but by a constant influx of people from without. Peasants driven off the land, perhaps by hunger or warfare, or the search for work, failed harvests. And these newcomers, in large numbers, to use contemporary medical jargon, were immunologically naïve; that is, they were susceptible and added to the pool of susceptibles in urban centers.

In every generation or so, urban centers, whose children had already suffered smallpox as an endemic childhood disease, suffered major epidemics among not only children but young adults, adolescents and older people. So, smallpox is an example of a disease — and we'll see malaria as another one — for which there's no simple distinction between endemic and epidemic. Smallpox was both endemic year in and year out, in Europe, and it was also epidemic sporadically every generation or so. It thrived in crowded urban environments, with throngs of people, and poorly vented houses and workshops.

Now, in the eighteenth century, statistics are elusive. But smallpox is commonly thought — and this is just a guesstimate — to have caused perhaps a tenth of all deaths in the century in Europe, and a third of all deaths among children under ten-years-of-age. Half the population of the continent is estimated to have been scarred or disfigured by this disease. And smallpox was also the leading cause of blindness.

Across Europe, perhaps half-a-million — this is again only a guesstimate — people died annually from this disease. In other words, it was the equivalent of — the largest city in Europe at the time, in the eighteenth century, was Naples, with half a million people — it was if a city of that size disappeared from this single disease every year. The nineteenth century English poet and historian, Thomas Babington Macaulay, wrote this about smallpox. "The havoc of plague had been far more rapid. But the plague has visited our shores only once or twice in living memory. But smallpox was always there, filling the churchyards with corpses, tormenting with constant fear all whom it had not yet stricken, and leaving on those, whose lives it spared, the hideous traces of its power, turning the babe into a changeling, at which the mother shuddered, and making the eyes and cheeks of the betrothed maiden objects of horror to her lover."

Two of the most famous descriptions of smallpox in this century were those that described it as "the speckled monster" and "the most terrible of all the ministers of death." Furthermore, like plague though, smallpox was an airborne disease — unlike plague — but like influenza. And it was an affliction that was universal, and had no predilection for any subset of the population, such as the poor. It wasn't really in that sense a social disease. Even royal families were scourged by smallpox in the seventeenth and eighteenth centuries. Famous sufferers and victims included King Louis XIV and Louis XV of France; William II of Orange; Peter II of Russia; the Holy Roman Emperor, Joseph I.

In England, smallpox was even directly responsible for a dynastic change. It extinguished the House of Stuart. The last Stuart heirs to the throne all died of smallpox, between the death of Queen Mary, in 1694, and the death of eleven-year-old Prince William, also from smallpox, in 1700. So this was a clear case in which a disease produced a constitutional crisis, and led to the Act of Settlement of 1701, that prevented another Catholic from being crowned, and brought in the House of Hanover. So, smallpox had a major impact in Western Europe. But its impact is not a simple repetition of the story of plague.

Chapter 2. Public Responses [00:11:39]

Although it was dreaded, smallpox did not give rise in Europe to mass hysteria, scapegoating and a religious frenzy. And there are reasons for that we can surmise. Unlike plague, smallpox was not a sudden outside invader that took society by surprise. Nor did it maximize its fury by targeting young adults and the middle-aged, who were the mainstays of families and of the economy. Smallpox was an endemic disease that was ever-present, and so it was considered almost normal, especially because it targeted infants and children, as a rule; although, as I've said, it did lead sporadically to broader epidemics. So, as a result everyone had some experience with smallpox, and half the people you might meet on the street, in a city of Western Europe, would be pockmarked, as a reminder of its passage.

So familiar was smallpox that it bred a kind of fatalism, the belief that it was inevitable in people's lives. And this attitude was so pervasive that it wasn't uncommon even for parents to expose healthy children intentionally to mild cases, in the hope that they could protect them from something much more catastrophic. We could look at this attitude by — or appreciate it — by thinking about European literature, particularly British literature, let's say in the eighteenth century. Let's think, for example, of Henry Fielding's novel Tom Jones. In that, when it was useful to have a change in plot, all the author had to do was to introduce the idea of smallpox, because no one would question that that was appropriate, or consider that this was a clumsy or artificial artifice.

Everyone expected smallpox. And in Fielding's novel, Joseph Andrews, we find that there's a heroine who is pockmarked. Or consider Thackeray's The Adventures of Henry Esmond, set in the eighteenth century, where smallpox drives the plot. Smallpox, quite simply, was just there, and it came to seem, for many people, a terrible but everyday part of the human condition. So, smallpox didn't cause great European cities, like London, to empty of their population, when people took the road in flight, as plague did in the seventeenth century and, as we shall see, that cholera was to do again in the nineteenth century. And there wasn't an urge to seek scapegoats for what seemed an almost natural or normal event. But this is a generalization, and there are reports of some who lost their nerve at the approach of smallpox and sought refuge in flight.

Let's return to our novel, Henry Esmond. There's a heroine, Lady Castlewood, who contracts smallpox as an adult, in a country village. Her husband — and this was surprising because we're told early on that he was an extraordinarily brave soldier, but he was a man who couldn't bear to face a disease that he couldn't fight and threatened him, not only with death, but this seemed to matter perhaps more to him than death itself — he thought he was extremely handsome and he was afraid that he would be maimed if he survived. So, unwilling to put his fair complexion, and his even fairer hair, at risk, Lord Castlewood took to his heels, and he deserted his household for the duration. But he wasn't part of a mass exodus. Although Thackery does have Henry Esmond, the hero of the story, tell us himself that smallpox was, in his words, "the most dreadful scourge of the world."

We also know that as a result of her ordeal, Lady Castlewood lost her beauty, and that her gallant husband, on his return, no longer loved her as he once did. As readers then, we know that one of the effects of smallpox was that it had a big impact on the marriage market. It disfigured people and made them less likely to succeed in those sweepstakes. We learn that Lady Castlewood, according to the author: "Her beauty was very much injured by the smallpox. When the marks of the disease cleared away, the delicacy of her color and complexion was all gone. Her eyes had lost their brilliancy. Her hair fell and her face looked old. It was as if a coarse hand had rubbed off the delicate tints of that sweet picture, and brought to it a dread color. Also it must be owned, her ladyship's nose was greatly swollen and red."

In any case, as you can imagine, having scars and pockmarks was also a source of great psychological distress and unhappiness, and this too was part of the plot of Thackeray's novel as it unfolds, and part of what we should remember as the impact of smallpox on the terrible eighteenth century. But that was smallpox in Europe: a major source of anxiety; a major impact on population; a source of the Cult of Saint Nicaise; a major factor in demography.

Chapter 3. Smallpox in the New World, Australia, and New Zealand [00:18:18]

But there's a more dramatic story that we need to come to, as we cross the waters and turn to the New World, or also Australia and New Zealand.

This is the story of what happened when the disease was suddenly introduced to populations in part of the world where it was a new invader; where it arrived from outside, had never been an endemic infection and therefore against which the native or aboriginal population had no immunity at all. Then it produced real catastrophes, events described as "virgin soil epidemics." These were catastrophes that accompanied European expansion to the New World, Australia, New Zealand. And there smallpox, and another childhood disease that accompanied it, measles, had a transformative importance in clearing the land and promoting settlement by Europeans with their robust immunity. The impact of smallpox and measles was greater than that of gunpowder.

In the New World, you'll be reading about this in detail in that wonderful book by Elizabeth Fenn, Pox Americana, and you might want to be reminded of the simple fact that the author was actually a Yalie, and that the book that you're reading began life here, as a Ph.D. dissertation. In any case, though, I want to have a division of labor between the lectures and the reading, and so I won't repeat the story that Fenn tells so movingly and so well. But there are a few points that I would like to highlight as specific examples, and a couple of general points. And first the general idea we should remember is that of something sometimes referred to as "the Columbian exchange." That is to say that the European encounter with the New World brought about the large-scale exchange from one side of the Atlantic to the other, and in the reverse direction, of fauna and flora.

Certainly, as you know, Europeans brought back the potato, maize and quinine, as examples, from the Americas. And there's been a debate as to whether this also involved a microbial component. And there are those who speculate that Columbus and his sailors brought back the disease syphilis, as well from the New World. We'll be returning to that argument later in the semester, when we come to talk about syphilis as a disease. What's beyond doubt though is that there was also a terrible movement of microbes in the other direction, as Europeans unintentionally introduced smallpox and measles to the Americas.

Let's illustrate with a specific example of the Columbian exchange — the exchange Fenn tells us about — by looking at this much-travailed island of Hispaniola, the mountainous Caribbean island where Columbus landed in the 1490s. Hispaniola — that is, what is modern Haiti and the Dominican Republic. And as we know from today's news, Haiti has a long history of natural and manmade catastrophes, and the arrival of Columbus was certainly one. The aboriginal inhabitants, a tribe known as the Arawaks, are estimated, or guesstimated, to have numbered something like a million people in 1492. Columbus described Hispaniola as almost an earthly paradise, a place of great natural beauty. And he reported that the Arawaks were a welcoming and non-warlike people, who greeted the Spanish warmly and showed them great kindness. But unfortunately for them, the kindness wasn't reciprocal.

The Spaniards were interested in profit, and international power politics. And Hispaniola was strategically located. It also possessed fertile soil, a favorable climate, and land that the Spanish Crown coveted for cultivation. So, European interest was based on commerce, profit and international power considerations. The Spaniards militarily dispossessed the Arawaks of their land, and intended to reduce them to slavery, first in mines and then on the land. They were assisted in the process, up to a point, by two great assets: gunpowder and disease. And as you know from reading Fenn, the aboriginal population of the Americas lacked immunity to European diseases like smallpox and measles.

There's no evidence that there was a plot of genocide or bioterror in the intentional use of disease as a means to clear the land and resettle it. What happened was spontaneous, and not intentional. But the encounter between the Europeans and the indigenous peoples of Hispaniola resulted in an extraordinary and terrifying die-off. Between 1492 and 1520, the Native population was reduced from a million people to 15,000. Disease thoroughly cleared Hispaniola for European colonization, virtually without resistance. On the other hand, smallpox thwarted the Spanish intention in Hispaniola to enslave the aboriginals. They simply died off at too extraordinary a rate. It therefore led the Spaniards, out of necessity, to turn to a different source of labor for mines and plantations. And since Africans and Europeans shared disease reservoirs that were partially overlapping, their people were resistant to many of the same epidemic diseases that had destroyed the Native Americans.

So, disease was a major factor in the establishment of the African slave trade and the development of New World slavery. The Spaniards hardly delayed. 1517 marked the beginning of the importation of African slaves to Hispaniola. Santo Domingo, by 1789, received into its ports every year some 1,600 ships, employing 24,000 sailors. And it accounted for 11 million pounds of the French total of 17 million pounds of exports. Its trade was the foundation of the wealth of port cities, like Nantes, Bordeaux and Marseilles, its cotton, a basis for the French textile mills in Normandy, and the growth was exponential. Between 1783 and 1789, production doubled, and with it the importation of slaves: 10,000 a year in 1764; 15,000 in 1771; 27,000 in 1786; 40,000 in 1787. The leading port of Santo Domingo, the prosperous city of Le Cap-Francois, had 20,000 people and was called "the Paris of the West."

The Columbian exchange played a major role in the history of Hispaniola, and that was writ large in the New World as a whole. A similar story could be told about Hernan Cortez and his fellow conquistador, Francisco Pizarro, with regard to the Aztec Empire of Mexico and the Incan Empire of Peru, which were destroyed not only by gunpowder, but also by smallpox, that destroyed agriculture, led to famine, destroyed the aboriginal military capacity to resist, and had, we're told, a tremendous psychological impact, because their gods seemed not to protect them. And, so, there was a wave of conversion to the European god, who seemed to protect his own people.

Now, you also know, from reading Elizabeth Fenn, that although this process was primarily unintentional, there were moments within it, within the larger catastrophe, of occasional acts of intentional genocide. And one was by Lord Jeffrey Amherst — whom we're portraying here — who intentionally gave Native Americans infected blankets. I thought I'd perhaps tell you a little anecdote that I won't vouch for historically. I know of it from oral history, from friends I had at the time who attended Amherst College and told me about a demonstration that I think took place in 1968. But that was that the plates — you've just seen Lord Jeffrey, who actually intentionally aimed at the die-off of aboriginal populations, and intentionally gave Native Americans blankets infected with smallpox scabs.

Well, the plates at Amherst College in the 1960s looked like this, and they show Sir Jeffrey scourging the Indian population with a whip, on horseback. And, so, in 1968, learning about the experience of genocide, there was a demonstration when the students of Amherst College stood up and smashed all the plates in the dining hall. In any case, it was also the case that this sort of tremendous die off that affected the Americas, cleared the land for European settlement, was repeated, again not intentionally, but with regards in Australia to the Aboriginals, and in New Zealand with regards the Maoris. But you have that story told vividly, and on a large canvas, by Elizabeth Fenn's Pox Americana. So, I'll leave you to read about that.

Chapter 4. Inoculation [00:30:34]

I'd like to turn now to our third point of the morning, which was the importance of smallpox for an entirely different reason, and that is the development of a new and major public health strategy; the strategy of inoculation initially, and that becomes more definitively the strategy of vaccination. Well, let's begin with inoculation. What is inoculation? It was an empirical practice — we might call it a folk art — and it was developed in various parts of the world as a result of two very simple observations. The first was that smallpox was clearly contagious. The second was that those who had recovered from the disease — and it was easy to know who had suffered from it because they were scarred and pockmarked, or also they were often blind — and it was a simple observation that they never caught smallpox a second time.

So, the idea developed that it might be a wise measure to induce a mild case of smallpox artificially, to protect a person, or especially a child, from the risk of acquiring a naturally occurring but severe and life-threatening or maiming case. And the practice that resulted was called variously inoculation, variolation, or, in a gardening metaphor, engrafting. There were variations, but the major technique was that liquid material from a smallpox pustule — you saw those last time — of a patient selected for having a very mild case was allowed to soak into a thread. The thread was then inserted into a superficial cut, made with the lancet — this sharp instrument that you've seen pictures of, in an earlier lecture — into the arm of the person to be protected, and fastened there for twenty-four hours. Twelve days later, the subject usually fell ill with smallpox; hopefully suffered from a mild case for about a month; convalesced for a further month; and then remained immune for a lifetime; hopefully not pockmarked or blinded.

This practice of inoculation was common in places like Turkey in the eighteenth century, but not in Western Europe. A major role in bringing this practice to Britain and Western Europe was played by this lady, the wife of the British Ambassador to Turkey, Lady Mary Montague, who lived from 1689 to 1762. And she was preoccupied with smallpox, in part because her own beauty had been compromised by a severe attack of the disease, and she elected to protect her own children by having them inoculated, by the practice I've just described, while they were in Constantinople. She returned to England in 1721 and launched a one-person, a one-lady, mission to convince society to introduce the practice of inoculation. She devoted herself to propagandizing British society in the practice. She was able to convince the Princess of Wales, who had her daughters inoculated, and the practice spread rapidly.

This was the first major public health advance in dealing with smallpox. And, as I tried to suggest last time, I would argue that it had a role — note that I'm saying only a role, not the role — as part of the background for the coming of the Enlightenment. Indeed, leading philosophes became ardent advocates of inoculation; people in France, like Voltaire and Charles de la Condamine; or on this side of the water, people we might also describe as philosophes, like Benjamin Franklin and Thomas Jefferson. Inoculation, appropriately, gained most favor in England; the epicenter, perhaps, of smallpox in Europe. But it gradually spread also to France, Holland, Germany, Sweden. In Russia, the procedure was introduced by Catherine the Great, who imported an English physician to inoculate her in 1768, after which the nobility rapidly adopted the practice.

The cresting wave then, of the smallpox epidemic, in the eighteenth century in Europe was met by the first practical measure of public health against it. Well, why did inoculation work, at least to the extent that it did? And I would say that inoculation was a partial success. Biological processes were at work that are still poorly understood. But there are a couple of relevant factors that we could note. One was that as a matter of practice, this procedure took infective material only from very mild cases. That was — the selection then of cases was one reason behind its success. The infective matter also was made to enter the body through the skin, in a way that doesn't happen in nature, and, for reasons that aren't understood, attenuates the virulence of the virus. So, the portal of entry into the body also seems to have made a difference. And lastly, for all that one knows, those who were inoculated were also selected, and you were only chosen for inoculation if you were healthy and robust.

There were, however, problems. Inoculation was also a partially flawed procedure. All too often, despite all precautions, it failed to produce the desired mild infection, but led instead to severe illness and death; and invariably it caused a month or two of immense suffering. It was also costly, since physicians insisted on a lengthy period of preparation when they were performing the procedure. Wanting to ensure that those they inoculated were in excellent health, they selected patients carefully, and then isolated them for a month before the procedure, during which they regulated their diet, their fresh air, their exercise; and this was obviously an expensive process. So, inoculation was simply not accessible to the poor.

Another factor was that inoculation could run the risk, because it introduced actual smallpox cases, and therefore it ran the risk of setting off an epidemic, unintentionally, that those who contracted the disease would then spread it to others around them. And to prevent that, smallpox inoculation hospitals — such as one in London, that opened in 1746 — were set up to care for the patients who'd been inoculated, and to quarantine them, so that they were no longer a risk to others. But nevertheless, there was a spirited debate over the whole issue of whether, on balance, inoculation saved many more lives than it killed.

Chapter 5. Vaccination [00:39:41]

Well, that brings us to this figure, a decisive figure in the history of medicine and public health, and that is Edward Jenner. It was in the context of this smallpox catastrophe of the eighteenth century, and of disappointments and anxieties surrounding inoculation, that we see a decisive discovery in the history of medicine and public health, associated with this English country doctor. To understand what happened, we need to remember what we said last time; and that is that there were three species of the genus of orthopoxviruses: Variola major, Variola minor, and cowpox. The first two are exclusively infectious to human beings, but the third mainly affects cattle. But the point is that, under the right conditions, cowpox can be transmitted to humans, among whom it induces a mild illness, but it provides — and this was the crucial point — a robust crossover immunity to Variola major.

Now, in Britain, the people thought most likely to contract cowpox were milkmaids. And Jenner — and this is why I stressed that he was a country doctor; this is his home in Barkley in Gloucester, in the west of England — he made an observation that could only have been made by a doctor with a rural practice, in a dairy county, at a time of severe prevalence of smallpox. And this observation was that milkmaids never seemed to come down with smallpox. Jenner, like others — he wasn't the first to make this observation, but he took it to heart and attempted the next step of an experimentation.

A crucial experiment occurred in 1796. The milkmaid Sarah Nelms contracted cowpox, and this is the — we'll see the experiment. Edward Jenner took the infective material from Sarah Nelms and vaccinated the eight-year-old son of his gardener, on his property, in 1796, and then, after a period of time, had a challenge in vaccination with live smallpox virus. And happily the experiment was a great success, and Edward Phipps demonstrated that he was immune, by this procedure, to smallpox. And, so, soon thereafter, Edward Jenner — whatever one thinks, by modern terms, of the medical ethics of that particular experiment — in 1798 Edward Jenner wrote one of the most influential works in the history of medicine, inquiring into the causes and effects of the Variola vaccinae.

His genius was not just to devise the experiment; that was scientifically flawed, perhaps, in the sense that he extrapolated from a very small database. But in any case, the point is that he recognized the significance of what he'd discovered. He thought that he saw immediately the possibility of eradicating smallpox from the planet, an idea whose importance the British Parliament recognized soon afterwards when it declared vaccination, "the greatest discovery" — I'm quoting — "in the history of medicine." Jenner wrote, in 1801, that he longed for, "the annihilation of the smallpox, the most dreadful scourge of the human race. That must be the final result of this practice."

So, Jenner had the genius to see the full implication of his discovery, and then he devoted the remainder of his life single-mindedly to the cause of promoting this revolutionary method, not only in Britain but also globally. It was also the first example of a new and highly effective style of public health, by vaccination, a method that's proved its effectiveness; certainly with regard to smallpox, but you could also mention polio, tetanus, rabies, influenza, diphtheria, shingles, and a host of other diseases. And Jenner soon made influential converts, who established vaccination as a major instrument of public health: Napoleon in France, Pope Pius VII in Rome, Benjamin Waterhouse and Thomas Jefferson on these shores.

Jenner's method, then, was a means to combat smallpox. And unlike inoculation, vaccination didn't introduce an infection of smallpox itself, and therefore had no risk of setting off an unintended epidemic. It also had a low risk of serious complications for the individual patient, and no risk at all for the community. But there were problems with Jenner's method, and it was to require a series of subsequent improvements to make vaccination a fully successful procedure. The problems involved such things as he required, at the time, an arm-to-arm method, and this entailed the risk of spreading other diseases, in particular syphilis, while trying to present smallpox.

There were also failed vaccinations that led to complications, and Jenner made a crucial mistake. He made it an article of dogmatic faith that the immunity derived from smallpox vaccination artificially was life-long, just like the natural immunity that was acquired, and he steadfastly refused to consider evidence that ran counter to his dogma. In fact, artificial immunity wears off, it's now known, after a period that's not quite understood, but ten, fifteen, twenty years, and requires, to still be valid, re-vaccination. This blindness on Jenner's part discredited vaccination in some quarters, and was one factor — these various limitations then — for one of the most powerful mass movements of the nineteenth century, and one that's still with us today, and that is the antivaccination movement.

Vaccination became one of the contested debates of nineteenth-century medicine. In Britain, an Antivaccination League was founded, and became a major political influence. There were various sources of opposition. There was the empirical observation of failure, as I've said, when people who had been vaccinated actually contracted smallpox. There was the opposition of liberals and libertarians to what they regarded as the excessive power of the state in making vaccination compulsory. And there was religious opposition, people who considered it an act of impiety to introduce material from animals into a human body, and there were sardonic posters featuring people undergoing vaccination while they sprouted horns or turned into cows.

But despite vaccination, there was, in Britain, an Act of 1840 that provided for free infant vaccination. And from that time, the annual toll from smallpox began to plummet, despite the fact that the nineteenth century provided conditions that would have been favorable to promoting the disease: improved and speedy transport, with steamships, canals and the railroads; crowding with a population that was ever more mobile, massive growth and urbanization and large cities. And those changes and advances were reproduced across Europe and North America.

And there were technological improvements as well — all of which leads me to the end of this morning — which is to say in 1959, the World Health Organization undertook the unprecedented step of launching a global smallpox eradication program by means of vaccination. In 1977, the final natural case occurred. And in 1980, smallpox was declared, by the WHO, eradicated everywhere on the globe. So, vaccination then comes with this extraordinary history of public health, of combating a major disease like smallpox and actually eradicating it.

What we'll want to do, as we move through the course, is to ask what are the conditions that make vaccination an appropriate tool for public health? When is it not appropriate? Why are there such difficulties with poliomyelitis, as we're speaking today? Was smallpox the beginning of a wave of diseases to be eradicated this way, one by one? Or was smallpox an exception, a special case? Well, stay tuned, and we'll deal with that.

[end of transcript]