The Rise and Practice of Inoculation in the 1700s

Overview

The 1700s saw the increased use of inoculation against disease as a medical practice. More importantly, the practice began to be used scientifically, with less chance of accidentally infecting those who were to be protected. By the end of the century, although some of the scientific principles were still not fully appreciated, inoculation and immunization had become more commonly used and were on their way to becoming the boons to public health they are today.

Background

Throughout human history infectious disease has claimed more lives than virtually any other cause. Even today, with the exception of the minority of people living in the developed world, infectious disease is the world's dominant killer. Smallpox, tuberculosis, rabies, polio, diphtheria, yellow fever, and many other illnesses have afflicted people for millennia, while emerging diseases such as Ebola, AIDS, and Legionnaires disease arise periodically.

It is also true that, for most of human history, we have had virtually no way to prevent or to combat infectious diseases. Thus, Europe was decimated by the Black Plague, Native Americans were destroyed by smallpox, and Africa is being torn apart by AIDS today. The discovery of germs, sterilization, and public health measures have helped immeasurably in the prevention of disease, while the discovery of antibiotics has helped cure many diseases that, earlier, were nearly always fatal. However, even these measures will only go so far because they leave individuals susceptible to disease organisms, and those organisms are always present, waiting to attack. Something more was needed.

At some time, unrecorded in any history, someone noticed that nobody became ill with smallpox more than one time. Those who had smallpox and survived were protected from the disease for the rest of their lives. It is not known how long ago this was first observed, but it is known that by the seventeenth century, Turkish medicine included inoculating healthy people with fluids from smallpox sufferers, hoping to transmit this immunity. We now consider this a dangerous practice and, indeed, some people did develop the full-blown disease. However, it was more typical for a person to develop a minor case of smallpox, recover, and never have to fear it again.

This practice of inoculation was brought to England by Lady Mary Montagu (1689-1762) in the early 1700s. She spent many years advocating its use, partly because she had survived smallpox years earlier and still bore its disfiguring scars herself. She enjoyed some limited degree of success, including seeing inoculation spread to the American colonies in the 1720s, when Zabdiel Boylston (1680-1766) introduced the practice in the wake of a smallpox epidemic in Boston. His efforts were encouraged by the preacher Cotton Mather (1663-1728), whose son nearly died of the disease.

Unfortunately, early efforts at inoculation were often met with responses ranging from skepticism to outright hostility. In Mather's case, at one point a bomb was thrown through the window to his house in protest against his support of inoculation. In England responses were somewhat more subdued, but no less skeptical. Some of the protest was religious in nature, especially from the more conservative believers who felt that disease and premature death were part of God's will, and it was sacrilege to attempt to forestall them (incidentally, some religions today continue to hold similar beliefs). In addition, because inoculations used live viruses from an infectious patient, some of those inoculated developed the disease and became infectious themselves. The knowledge that one could die from a measure that was supposed to protect helped stir fears and arouse anger in many of the general public. All of this helped to slow the spread of inoculation as a preventative medicine practice. However, by the latter part of the eighteenth century, the practice of inoculation was becoming increasingly accepted, even though it was not yet widespread.

In 1796 English physician Edward Jenner (1749-1823) discovered that cowpox sores, similar to those of smallpox, could be used to inoculate someone against smallpox. When finally accepted by physicians elsewhere, cowpox inoculations became increasingly common.

Impact

The rise of inoculation to help prevent smallpox was a qualified success in the short term. Its long-term impact, however, may be considered an almost unqualified success story. Nevertheless, in spite of the dramatic drop in death by infectious diseases since the advent of widespread immunizations, not all of the outcomes have been beneficial. Four major impacts of inoculation are:

1. The development of an ever-increasing number of vaccines
2. A dramatic reduction in death from infectious disease in most of the world, with a corresponding rise in death from heart disease and cancer
3. An increase in human lifespan in many nations and a decrease in child mortality rates
4. A corresponding increase in population in many nations

The most obvious impact stemming from inoculations is the subsequent development of vaccines to prevent other disease. Since that time, former scourges such as rabies, polio, measles, German measles, diphtheria, whooping cough, and yellow fever have been largely eliminated through the use of vaccines. We no longer expect children, at least in the developed world, to fall ill with an endless succession of potentially fatal diseases. Instead, we immunize them against the most common diseases and rely on medicine to cure those suffering from anything else.

It is primarily the developed world that enjoys this sort of protection, and it is primarily in the developed world where death from infectious disease has fallen so dramatically. However, it must be noted that a large-scale immunization program was carried out against smallpox, resulting in it being declared eradicated by the United Nations in 1977.

As a result of this wider access to vaccines against a widening number of diseases, global death rates from infectious disease have been dropping for some time. There has recently been somewhat of a leveling off of these rates, primarily due to the AIDS epidemic, but the general trend continues to drop because of efforts to immunize children whenever possible.

A corollary of this drop in death by infectious disease is a corresponding rise in death from other causes, including cancer and heart disease in much of the developed world. Much of the reason for this is simple mathematics. Everyone is destined to die of something at some time. If any single cause of death is reduced greatly, then all others must increase. To look at it another way, suppose that there are only four causes of death, and they all are equally probable. This means that, say, cancer, heart disease, infectious disease, and accidents each cause 25% of all deaths. Now, suppose that there are no more deaths from infectious disease because medicine has developed perfect vaccines and antibiotics. This means that the death rate from the remaining three causes of death must increase to 33% each because they are still equally probable, and nobody lives forever. So, as a result of our progress against infectious disease, cancer and heart disease have become more prevalent in society, because people are now living long enough to develop them.

In addition, for perhaps the first time in human history, we can expect virtually every child to live long enough to reach a healthy adulthood. While this is still not the case in many parts of the developing world, it is true in the developed world, largely because of the ubiquity of childhood immunizations (increased nutrition and improved pre- and postnatal care are other important factors in this). On a related note, families are now smaller than even just a century ago, and population growth has slowed in many parts of the world.

However, population growth has not slowed in much of the developing world, and this is again partly due to improved vaccination programs (and, as above, also partly due to better nutrition and medical care). As a result, many developing nations find themselves with a booming population because families are still having a large number of children, most of whom are now living longer lives. As this increased population of children reach adulthood, they, too, have large families, and more of their children are surviving. So populations grow at an even faster rate, placing further stress on infrastructure, populations, and governments that can ill afford it.

Taken at its most simplistic, we can look at vaccines this way: they have helped to greatly reduce early death from infectious disease in favor of a later death from other causes. From this perspective, their primary contribution has been to lengthen human life in most parts of the world. In addition, vaccines against nonlethal diseases have saved people untold suffering from disease, and further suffering for those who would otherwise have spent much of their lives crippled or injured in some other manner by the disease. Inoculation and vaccination has helped millions of children to reach adulthood, and there is little doubt that some of them have gone on to live rich lives full of accomplishment. In this sense, vaccines have helped make the world a better place, and have made lives longer and fuller than might otherwise be the case.

However, no blessing is unmixed. The irony is that, as vaccines have helped lengthen human life, they have also contributed to population growth, shortage of natural resources, the increase of heart disease and cancer as causes of death, and financial stress on third world governments.

P. ANDREW KARAM

Further Reading

Baxby, Derrick. Jenner's Smallpox Vaccine: The Riddle of Vaccinia Virus and Its Origin. London: Heinemann, 1981.

Bazin, Herve. The Eradication of Smallpox: Edward Jenner and the First and Only Eradication of a Human Infectious Disease. San Diego: Academic Press, 1999.

Stolley, Paul and Tamar Lasky. Investigating Disease Patterns: The Science of Epidemiology. New York: Scientific American Library, 1995.