What is vaccination?
Nowadays, we use the word ‘vaccination’ to describe a procedure in which a patient is inoculated with an antigen (a ‘vaccine’) to produce immunity against a disease. Common vaccines used in the UK include the flu vaccine, the chicken pox vaccine, the MMR vaccine (for measles, mumps and rubella) and the HPV vaccine (for cervical cancer).
(Right)A girl receives a measles vaccination. Photo by Belinda Hankins Miller. © Creative Commons The word ‘vaccine’ comes from the Latin word for cow, and it was first used to describe Edward Jenner’s use of cowpox matter to immunize against smallpox. (See module ‘Jenner’s Breakthrough’). Jenner had no idea why cowpox was effective against smallpox; he was simply acting on hearsay evidence. But his experiment proved a vital breakthrough in the struggle against a disease.
Later in the 19th century the French scientist Louis Pasteur experimented with antigens to combat anthrax and rabies, and he called these antigens ‘vaccines’ in Jenner’s honour.
Vaccination vs ‘Variolation’
Inoculation against smallpox (‘variolation’) was a common procedure in Britain for almost a century before Jenner carried out the first vaccination. Both vaccination and variolation work by boosting the body’s immune system, stimulating the natural production of anti-bodies that combat disease. But whereas vaccination involves the use of a cowpox vaccine, variolation involves inoculation with live smallpox matter.
Performed effectively – with a mild dose of smallpox, administered just under the skin – variolation is very effective, and the most skilful variolators in the 18th century were achieving impressive results in the fight against smallpox. But there are two significant problems with variolation.
(Right) A watercolour by G. Kirtland comparing the effects of smallpox inoculation (variolation) on left, and cowpox inoculation (vaccination) on right – reaction on arm after 14 days. 1802. © The Wellcome Library, London First, by introducing live smallpox matter into the body, there is always a risk that the patient will contract a full-blown case of the disease. Approximately two out of every hundred patients variolated against smallpox in the 18th century died. (Edward Jenner himself was variolated as a child; he ran a high fever and barely survived).
The second problem with variolation is that, after the procedure, the patient is contagious, and can spread smallpox to others. Variolation was only safe if the patients were quarantined in hospital, or in special ‘smallpox’ houses, for a fortnight after the procedure.
Vaccination is far safer than variolation. Side effects (for instance, fatal inflammation of the brain) are known to have occurred, but so rarely as to be statistically negligible. And because vaccination patients are inoculated with cowpox and not smallpox, there was no risk of smallpox contagion.
Was Jenner the first?
Edward Jenner is known as the "father of smallpox vaccination", and he dedicated his life, money and reputation to spreading the use of the cowpox vaccine. But in 1774, two decades before Jenner’s experiment on James Phipps, a farmer called Benjamin Jesty vaccinated his wife and children at Yetminster in Dorset.
(Right) A portrait of Benjamin Jesty, who inoculated his family with cowpox in 1774. © The Wellcome Library, London Jesty was aware of the age-old tradition that people who had earlier caught cowpox were thereafter immune from smallpox; his two dairymaids, Ann Notley and Mary Reade – both of whom had had cowpox – nursed smallpox victims without any ill effects. So when cattle on a nearby farm contracted cowpox, Jesty took his wife and children to the farm and carried out a vaccination procedure with a darning needle.
Jesty hoped to keep the procedure secret, to avoid the scorn of his neighbours, but his wife became feverish and a doctor had to be called. She survived, and went on to live a long and healthy life. But the story spread and Jesty was subject to local derision. Contemporary accounts describe how he was "hooted at, reviled and pelted whenever he attended markets in the neighbourhood”.The family moved to the Isle of Purbeck where a gravestone records the story.Clearly, Jenner didn’t invent vaccination. But he was the first to conduct the experiment openly, in the name of medical science. And it was his championing of the vaccine that led to its adoption across the world. It is to Jenner – rightly or wrongly – that the credit is given for a vital breakthrough in the battle against disease.
The ethics of Jenner’s experiment
Some modern commentators have criticised Jenner for what they consider to be unethical conduct. His behaviour – using a child in a speculative experiment – has been likened to the atrocities performed by Nazi doctors in the death camps in Poland in the 1940s.
Jenner’s behaviour can be justified for two reasons. First, because he had every reasonable expectation that the experiment was safe, and second, because of the benefits to mankind should the experiment prove successful.
Jenner vaccinating Edward Phipps. Oil painting by Earnest Board, 1920s. © The Wellcome Library, London His experiment involved a two-stage process. First, he introduced live cowpox into James Phipps’ arm. He knew that this would cause Phipps to contract cowpox; but cowpox was a mild disease, commonly suffered by dairymaids, with little negative effect – a few pustules, nothing more. Next, a couple of weeks later, Jenner tested Phipps’ immunity against smallpox by introducing live smallpox matter. This is more controversial. But in fact, all Jenner was doing was performing the common procedure of ‘variolation’. The worst that was likely to happen was that Phipps would have a mild smallpox reaction. And thereafter, Phipps would be immune from smallpox for life. Effectively Phipps was receiving, free of charge, an inoculation that was common practise at the time.
As it turned out, Phipps showed no reaction against smallpox – proving the effectiveness of the cowpox vaccine. And in gratitude for his part in the breakthrough, Jenner gave Phipps a house, which still stands in Berkeley, Gloucestershire, just down the lane from Jenner’s own home.
The vaccine controversy
Over the past thirty years, historians have debated the exact nature of the vaccine used in the 19th century.
The controversy stems from the fact that vaccine was harvested in a variety of different ways. The most pure way to vaccinate against smallpox is to harvest cowpox matter direct from the infected udder of a cow; but to do this, one needs to wait for a naturally occurring outbreak of cowpox in cattle, and cowpox occurs rarely. So vaccinators either deliberately infected cows with cowpox, or they took cowpox matter from the arms of humans who'd been vaccinated. Or - more controversially - they infected cattle not with cowpox but with smallpox, and they called the resultant infection 'cowpox'. But was it cowpox, or was it a cattle variant of smallpox?
Harvesting vaccine from a cow in the 1870s. © unknown Some modern virologists believe that the vaccine used to immunise people throughout the 19th century was closer in form to smallpox than cowpox; in other words, that vaccination was variolation by another name. The truth is we just don't know - and because no samples of 19th century vaccine survive, we may never know.
The remarkable fact is that Jenner's breakthrough was achieved without even a basic understanding of virology. Jenner made his discovery by intuitive guesswork, not through scientific knowledge. It wasn't until the end of the 19th century that the viriola virus was identified, and it wasn't until 1947 that it was first seen with the human eye, with the help of an electron microscope.
Even today, virologists don't understand the true nature of the relationship between the smallpox and the cowpox virus, or why vaccination with cowpox is effective against variola.