Edward Jenner's Smallpox Vaccine (1796): The First Vaccination

On 14 May 1796 the English country doctor Edward Jenner inserted material from a cowpox sore into the arm of an eight-year-old boy, James Phipps, in Berkeley, Gloucestershire. Weeks later he exposed the boy to smallpox, and Phipps did not fall ill. This experiment introduced vaccination, the first safe and reliable protection against smallpox, and began a medical revolution that ended with the global eradication of the disease in 1980.

Smallpox in the eighteenth century

Smallpox was one of the deadliest diseases in human history. Caused by the variola virus, it spread from person to person and killed roughly 20–30 percent of those infected, more among infants. Survivors were often left with deep scars, and some were blinded.

In eighteenth-century Europe the disease is commonly estimated to have killed around 400,000 people a year. It struck every class: Queen Mary II of England, the Holy Roman Emperor Joseph I and King Louis XV of France all died of it. In the Americas, smallpox had devastated Indigenous populations since the epidemic at Tenochtitlan in 1520.

Variolation: the earlier defence

People had long noticed that survivors of smallpox did not catch it again. In parts of Asia and Africa, healers practised variolation, deliberately infecting healthy people with material from smallpox sores to produce a milder case. The practice was introduced into Britain after 1721 through the efforts of Lady Mary Wortley Montagu, who had seen it in Constantinople.

Variolation saved many lives but carried real risks. Perhaps 1–2 percent of those inoculated died, compared with far higher mortality in natural smallpox, and inoculated people could pass full-strength smallpox to others. Jenner himself was variolated as a boy, an experience he remembered as harsh.

Jenner and the cowpox tradition

Edward Jenner was born on 17 May 1749 in Berkeley, the son of the local vicar. He was apprenticed to a surgeon near Bristol and in 1770 went to London to study under the celebrated surgeon and anatomist John Hunter, who encouraged him to test ideas by experiment. Jenner returned to Berkeley as a country doctor and was elected a Fellow of the Royal Society in 1789 for his observations on the nesting behaviour of the cuckoo.

In the dairy country of Gloucestershire it was widely believed that milkmaids who had caught cowpox, a mild disease that caused sores on cows’ udders and on the hands of those who milked them, did not catch smallpox. Several people had already acted on this belief. In 1774 Benjamin Jesty, a Dorset farmer, used cowpox material to protect his wife and two sons during a smallpox outbreak, and a few others did similar things. None of them, however, tested the idea systematically or published it.

The experiment of 1796

In May 1796 a young dairymaid named Sarah Nelmes came to Jenner with cowpox sores on her hand, caught, according to tradition, from a cow named Blossom. On 14 May Jenner took matter from her lesions and introduced it through two small cuts into the arm of James Phipps, the son of a labourer who worked for him.

Phipps developed a mild fever and some discomfort for a few days, then recovered. On 1 July 1796 Jenner variolated him with material from a smallpox sore. No disease followed, and later challenges gave the same result. Jenner concluded that cowpox had given Phipps protection against smallpox.

Jenner sent an account to the Royal Society, but it was not accepted for publication, and he was advised to gather more evidence. Cowpox outbreaks were sporadic, so he could only resume work in 1798. That year he published, at his own expense, An Inquiry into the Causes and Effects of the Variolae Vaccinae. The book described 23 cases, including people who had caught cowpox naturally and a series of children vaccinated from arm to arm.

The Inquiry was short but carefully argued. Jenner coined the Latin name variolae vaccinae, “smallpox of the cow”, and stressed that only “true” cowpox gave protection; other sores on cows’ udders, which he called spurious cowpox, did not. Some of his theories proved wrong. He believed, for example, that cowpox began as “grease”, a disease of horses’ heels, carried to cows by farm workers. Despite such errors, the core finding was sound and could be checked by anyone willing to repeat it.

Early trials also showed the risks of careless practice. Some vaccine distributed in London in 1799 had been taken from patients at a smallpox hospital and was probably contaminated with smallpox, producing eruptions that critics used against the method. Jenner insisted on clean material and correct technique, and he spent much of his remaining life answering questions from doctors around the world.

How vaccination spread

The new method spread with astonishing speed. Doctors such as George Pearson and William Woodville in London began vaccinating, and supplies of “vaccine lymph” were sent across Britain, Europe and beyond. Because there was no way to preserve the material for long, it was often carried by vaccinating people in sequence, passing the infection from arm to arm.

The most famous example was the Spanish Royal Philanthropic Vaccine Expedition led by Francisco Javier de Balmis, which sailed from A Coruña in 1803. It kept the vaccine alive by vaccinating orphan boys in turn during the Atlantic crossing, then carried it through Spanish America and on to the Philippines.

Napoleon had his soldiers vaccinated, and the American president Thomas Jefferson vaccinated members of his household and praised Jenner in a letter of 1806. The British Parliament voted Jenner grants of £10,000 in 1802 and £20,000 in 1807. He continued to promote vaccination, sending vaccine free to doctors and vaccinating poor people without charge at a small hut in his garden.

Supporters founded the Royal Jennerian Society in London in 1803 to provide free vaccination to the poor, and the University of Oxford gave Jenner an honorary doctorate of medicine in 1813. His home in Berkeley, with the garden hut he called the Temple of Vaccinia, is now a museum, Dr Jenner’s House.

Opposition and public health laws

Vaccination also met resistance. Some doctors who earned money from variolation opposed it, and some religious critics objected to introducing animal matter into humans. In 1802 the caricaturist James Gillray published a famous print showing vaccinated patients sprouting cows from their bodies.

Governments gradually made vaccination official policy. In Britain the Vaccination Act of 1840 provided free vaccination and banned variolation, and an act of 1853 made infant vaccination compulsory in England and Wales. Compulsion in turn provoked an organised anti-vaccination movement in the later nineteenth century, which led to exemptions for conscientious objectors in 1898.

Key people

• Edward Jenner (1749–1823): Gloucestershire physician who tested and published vaccination. He died in Berkeley on 26 January 1823.
• James Phipps (1788–1853): the boy vaccinated in 1796. Jenner later provided him with a cottage in Berkeley.
• Sarah Nelmes: the milkmaid whose cowpox sores supplied the first vaccine material.
• Benjamin Jesty (c. 1736–1816): Dorset farmer who used cowpox on his family in 1774, later recognised as a pioneer.
• John Hunter (1728–1793): Jenner’s teacher, who encouraged him to experiment.

From vaccination to eradication

Vaccination steadily reduced smallpox in countries with strong programmes, but the disease remained common in much of the world into the twentieth century, when it is estimated to have killed some 300 million people. In 1967 the World Health Organization launched an intensified global eradication programme, using mass vaccination plus surveillance and “ring vaccination” around new cases.

Technical advances made the campaign possible. Freeze-dried vaccine could survive tropical heat without refrigeration, and the simple bifurcated needle allowed health workers with little training to vaccinate large numbers of people with a small amount of vaccine. Teams searched villages for cases, isolated patients and vaccinated everyone around them, breaking the chains of transmission one outbreak at a time.

The last naturally acquired case was a hospital cook, Ali Maow Maalin, in Merca, Somalia, in October 1977; he recovered. On 8 May 1980 the World Health Assembly formally declared smallpox eradicated, the first human disease to be wiped out.

One more tragedy followed. In 1978 a medical photographer, Janet Parker, caught smallpox from a laboratory at the University of Birmingham and died, the last recorded death from the disease. Since then, officially acknowledged stocks of the virus have been kept only in two high-security laboratories, in the United States and Russia.

Myths and facts

Jenner is often called the “inventor” of vaccination, but he did not discover cowpox protection; farmers knew the folk belief and some had acted on it. His real contribution was to test it deliberately, publish the evidence and campaign tirelessly for its adoption.

Another myth is that today’s smallpox vaccine is simply cowpox. Modern genetic studies show that the vaccine virus used in the twentieth century, called vaccinia, is distinct from cowpox and is closely related to horsepox. Its exact origin in the nineteenth-century vaccine supply is still debated.

By the numbers

Timeline

• 1749, 17 May: Edward Jenner is born in Berkeley, Gloucestershire.
• 1774: Benjamin Jesty uses cowpox to protect his family in Dorset.
• 1796, 14 May: Jenner inoculates James Phipps with cowpox from Sarah Nelmes.
• 1796, 1 July: Phipps is variolated with smallpox and does not fall ill.
• 1798: Jenner publishes An Inquiry into the Causes and Effects of the Variolae Vaccinae.
• 1803: The Balmis expedition sails from Spain to carry vaccine to the Americas and Asia.
• 1823, 26 January: Jenner dies in Berkeley.
• 1853: Infant vaccination becomes compulsory in England and Wales.
• 1980, 8 May: The World Health Assembly declares smallpox eradicated.

Why it matters

Jenner’s experiment on James Phipps created the first vaccine and the very word vaccination. It showed that a mild, related infection could train the body to resist a deadly one, an idea later extended by Louis Pasteur and the makers of every modern vaccine. Its ultimate result, the end of smallpox, is one of the greatest achievements in the history of medicine.