Defending Edward Jenner

First broadcast November, 1997

It was only when Robyn introduced an Ockham's program on the importance of vaccination last year that I realised I had been remiss. It was my own fault: I simply hadn't been watching the time. You see, I knew that we had a bicentenary coming up for Edward Jenner's great experiment - indeed, I had assembled most of the relevant material about five years ago, in readiness for the great day.

I knew that people would be getting stuck into Jenner, for it's a common error. I even had an editor once, who lambasted me for failing to criticise, in a science textbook, that dreadful Jenner for putting at risk the life of a small boy. I stood firm then, and I must do so now.

Jenner did no wrong.

Assuming that Edward Jenner was naughty may be common, but it is nonetheless an error, based on a misunderstanding of medical practices in the late 18th century. The facts are simple: Jenner had heard that cowpox provided immunity to smallpox. James Phipps, a boy of eight years, was infected with cowpox from a pustule on the hand of Sarah Nelmes, a milkmaid who had cowpox, and some two months later, James was deliberately infected with variolous matter, part of a smallpox pustule.

But while the facts are simple, the interpretation is more complex. This act of Jenner's, say most reasonable scientists, is a piece of medical unethics, the sort of thing that'd get you struck off if you tried it today. Fair enough, most people would say - after all, Jenner did use an eight-year-old boy as a guinea pig didn't he?

Not exactly.

Jenner wasn't putting young James Phipps at risk or using him as a guinea pig: if anything, he was protecting him. It's just a little bit unwise to assume that medical ethics have changed so much over the past two hundred years. After all, Hippocrates was around a whole lot earlier than that, wasn't he? So if the action could be deemed unethical today, it would certainly have been called unethical then.

There was a huge to-do when Jenner first announced his results, but nobody accused him at the time of acting unethically. They said many other things about him, but they never said he was unethical. A year later, more than seventy of London's principal physicians and surgeons supported the Jenner method, and soon after, vaccination became as normal as the inoculation procedure that it replaced.

Why did Jenner's detractors not accuse him of an infamous breach of ethics? Maybe they knew a bit more about the context than we do today. And that context, once we understand it, shows absolutely clearly just how innocent of any wrong-doing Edward Jenner really was.

In the first place, let us consider the nature of immunisation. Today, we have two words that we use interchangeably: inoculation and vaccination. But once upon a time, when Edward Jenners walked the earth, the two words meant quite different things, though both had to do with causing immunity.

"Inoculation", I was once told, referred to putting the immunity-causing stuff in the eye. Not so, I'm afraid. The act of inoculation is a far gentler process. The word derives from the act of grafting a plant bud, an oculus, onto a different plant. In the immunity industry, inoculation had, and has, to do with the grafting of the target disease onto a new patient. If a weakened form of the disease can be found, that's handy, but if it can't be found, at least we can choose the time when we get the disease. Remember the idea of engrafting, because we will see it again.

In my youth, when you were immunised against TB, you were given an injection of live bacteria, BCG, Bacillus Calmette Guerin, germs which won't cause real TB, but which make your body wary of similar bacteria, including the ones which could cause real TB.

BCG is a strain of bacillus, taken originally from a cow, and cultured over a long period of time, during which it changed in some unknown way, so that it could give immunity to TB, but not cause the disease. In Lübeck in 1930, the inevitable happened when both the full strength tuberculosis bacilli and the BCG bacilli were cultured in the same laboratory.

When 251 newborn infants were injected, due to a tragic error, they were given the wrong bacteria. After four years, 47 of them had no sign of the disease, 127 were alive, but had "arrested" TB, and 77 had died. Two-thirds of a century on, the opponents of immunisation still like to trot out that isolated case as evidence of the dangers of mass immunisation.

The word "vaccination" has to do with cows. The Latin word for a cow is vacca, and the "vaccine disease", "vaccine pock", or variolae vaccinae were all names for the simple disease more commonly called cow pox by the people who suffered from it. So while the BCG bacillus also comes originally from cows, treatment with BCG is not strictly a form of vaccination.

And now it is time to look at how the first inoculations were arranged, and where they came from. First, keep in mind that you could get smallpox once and once only. If you survived the experience, you were safe from the disease forever after. You might be scarred by the disease, but you would never have to worry about catching the disease again. It was this observation which probably first led people to think of variolation.

"Variola" is medical Latin, and refers to the pustule or pox of the smallpox. This was the bud that could be grafted onto a healthy person in an inoculation. But that begs the question: why would you want to deliberately infect yourself with a potentially fatal disease? The answer is simple: if you think there is a 100% chance of getting smallpox, why not try to shade the odds your way, by choosing the field of battle, the time and the place to catch it?

Some people say this trick was followed first in Africa, that it was an old practice there, but our first historical record comes in a letter from Adrianople, written by Lady Mary Wortley Montagu in 1717.

"I am going to tell you a thing that will make you wish yourself here. The small-pox, so fatal and so general among us, is here entirely harmless, by the invention of ingrafting, which is the term they give it. There is a set of old women who make it their business to perform the operation every autumn, in the month of September, when the great heat is abated. People send to one another to know if any of their family has a mind to have the small-pox . . . There is no example of any one who has died in it; and you may believe I am well satisfied of the safety of this experiment, since I intend to try it on my dear little son."

The lady in question was famous in her day, though better recalled today for a celebrated falling-out with the poet Alexander Pope, but she was undoubtedly well-placed to spread the idea among the influential people of Britain. So going on the Montagu letter, the idea came to England in 1717, and for whatever reason, it seems to have spread fast.

Cotton Mather, who died in Boston in 1728, supported the practice, and is often credited in American books with inventing it, although it is possible that the idea was brought to America by black slaves. Certainly George Washington had his troops inoculated in 1776, and Napoleon Bonaparte had his troops treated in the same way, some two decades later. This same trick was also known in China, so we probably cannot be certain where it arrived in the European world, but we can say for certain that it arrived with a bang.

So the original treatment for smallpox (pre-Jenner) was deliberate infection at a time when people were otherwise healthy. The initial death rate from variolation was far lower, probably because people chose "mild cases" as their source of germs. While they did not know about bacteria or viruses then, they knew about strong and weak poisons, and would naturally have chosen, like Mithridates in the legend, the weakest "poisons".

By 1790, inoculation or variolation was a commonplace, just mentioned in passing, along with other daily events in the life of a quiet rural English clergyman. The Reverend Gilbert White was a careful observer of nature, as revealed in a set of his letters which were published in 1788 as The Natural History of Selborne, though given a 1789 date by his publisher, in order to make the book appear fresh longer. The attempt wasn't really necessary, for the letters retain their freshness and charm to this day.

But Gilbert White also kept a journal, and this reveals a wealth of fine detail about 18th century English life. In among scraps of poetry, records of wildflowers blooming, the cucumber crop, birds seen, the ripening of the strawberries, the numbers of eggs laid by the bantams, how much the tortoise weighs, and when the rhubarb flowered, weather records and other everyday occurrences, we find the following entries for the middle of 1790.

May 6 Mrs Chandler brought to bed of a daughter at the parsonage-house.

Sept. 21 Mrs Clement and six of her children, four of which are to be inoculated, and Mrs Chandler, and her two children, the youngest of which is also to undergo the same operation, are retired to the Harteley great house. Servants and all, some of which are to be inoculated also, they make 14 in family.

Sept. 27 The inoculated at Harteley sicken.

Oct. 13 Mrs Chandler returns home from the Harteley inoculation.

Dec. 29 On this day Mrs Clement was delivered of a boy.

In other words, variolation to the folk of Selborne was just part of the annual cycle, like the spring gales or the strawberry crop.

The pattern is clear: a group is selected to go into isolation, pregnant women like Mrs Clement were willing to expose themselves to the disease, a four-month-old baby is included, and so are adults who had not previously been exposed. And what voices do we hear raised in anger at the hideous behaviour of this English clergyman, conniving at exposing so many defenceless women, children and servants to this dreaful disease?

Not a one, because nobody minded!

Yet what Jenner discovered and did is usually wildly misrepresented by people unfamiliar with the medical standards of his day. It was probably during a discussion on variolation that a girl told Jenner about her natural immunity. Those who had suffered the mild disease of cow-pox never got smallpox, she explained.

Perhaps we could accuse Jenner of being wrong in subjecting a young boy to the infection of cowpox, but even that had been the subject of careful observation. But to understand this, we have to pursue Jenner's own carefully constructed studies. Here are some examples drawn from his An Inquiry into the Causes and Effects of the Variolae Vaccinae, published in 1798

"In April 1795, a general inoculation taking place here, Merret was inoculated with his family; so that a period of twenty-five years had elapsed from his having the cowpox to this time. However, though variolous matter was repeatedly inserted into his arm, I found it impracticable to infect him with it."

That wasn't enough for the cautious Jenner. He sought out other cases.

"Case II. Sarah Portlock . . . was infected . . . twenty-seven years ago. In the year 1792, conceiving herself, from this circumstance, secure from the infection of the smallpox, she nursed one of her children who had accidentally caught the disease, but no indisposition ensued."

Then after many other careful checks and tests, Jenner was satisfied that cowpox was safe.

"Case XVII. The more accurately to observe the progress of the infection, I selected a healthy boy, about eight years old, for the purpose of inoculation for the cowpox. . . . it was inserted on the fourteenth of May, 1796. . . .

"In order to ascertain whether the boy, after feeling so slight an affection of the system from the cowpox virus, was secure from the contagion of the smallpox, he was inoculated the first of July following with variolous matter, immediately taken from a pustule. . . no disease followed."

While variolation with smallpox was a much better risk than a genuine and unplanned attack of smallpox, but it was still a risk, and some people died of it. Jenner realised that if variolation with variolae vaccinae, the harmless cow-pox had the same effect as variolation with the risky smallpox, it would be an even better treatment. Vaccination was better than inoculation.

James Phipps was to be variolated in any case, so on May 14, 1796, Jenner treated him with liquid from a cowpox pustule. Two months later, James was variolated, but he did not develop smallpox. For the first time, the killer disease was deliberately beaten in a skirmish, though the war would lat another two hundred years.

But back to our vaccine that we use against smallpox, our variolae vaccinae, our cowpox. Is it correctly named? Apparently not, according to Sir Macfarlane Burnet, who wrote in 1971:

"The virus used for vaccination against smallpox has an obscure history. Nominally, it is a descendant of Jenner's cow-pox, but most virologists believe that it is a much mutated derivative of human smallpox virus that developed an acceptably low level of virulence during passage from human to human in the early 19th century."

But then, given how much else we fail to understand or realise about smallpox and Jenner's careful, ethical methods, what do a few minor slips like that matter?

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