Jenner, Vaccination & 18th-Century Medicine
Medicine in Eighteenth-Century Britain
The eighteenth century (1700s) was a period of gradual but important change in English medicine. By this time, the Enlightenment had encouraged thinkers to rely on reason, observation, and experiment rather than ancient authority. The Four Humours theory was losing influence among educated physicians, and supernatural explanations for disease were declining — though they had not disappeared entirely among ordinary people. Despite this shift in thinking, most treatments remained largely unchanged from earlier periods.
By the 18th century, the Four Humours theory was losing influence and supernatural explanations were declining, but most treatments for ordinary people remained largely unchanged — herbal remedies, bleeding, and purging were still common.
Smallpox: A Killer Disease
Smallpox was one of the most feared diseases in 18th-century Britain. It killed approximately 400,000 Europeans every year and left many survivors permanently scarred or blinded. There was no cure, and the disease struck people of all social classes — even monarchs and their children were at risk.
Before Jenner’s work, the main method of prevention was inoculation (also called variolation). This involved deliberately infecting a person with a small amount of pus from a smallpox blister, inserted into a cut in the skin. The patient would usually develop a mild form of the disease and then become immune. However, inoculation was risky — some patients developed full-blown smallpox and died, and inoculated people could spread the disease to others.
Edward Jenner and Vaccination
Edward Jenner (1749–1823) was a country doctor from Gloucestershire who observed that milkmaids who had caught cowpox (a mild disease caught from cows) seemed to be immune to smallpox. In 1796, Jenner decided to test this observation scientifically.
The Experiment
Jenner took pus from a cowpox blister on the hand of a milkmaid called Sarah Nelmes and inserted it into cuts on the arm of an eight-year-old boy called James Phipps. Phipps developed mild cowpox symptoms and recovered quickly.
The Test
Six weeks later, Jenner deliberately exposed Phipps to smallpox by inoculating him with smallpox pus. Phipps did not develop the disease — the cowpox had made him immune.
Publication
After repeating the experiment on more patients, Jenner published his findings in An Inquiry into the Causes and Effects of the Variolae Vaccinae. He called the process “vaccination” from the Latin vacca meaning cow.
Compulsory Vaccination
The Vaccination Act made smallpox vaccination compulsory for all infants in England and Wales. Scotland followed in 1863.
Jenner proved that cowpox vaccination could prevent smallpox, but he could not explain why it worked. The scientific explanation came later with Pasteur’s Germ Theory in the 1860s.
Opposition to Vaccination
Despite its success, Jenner’s vaccination faced significant opposition from several groups:
Inoculators opposed vaccination because it threatened their income. They had built profitable businesses performing inoculation and stood to lose customers. Some doctors were sceptical because Jenner could not explain the scientific mechanism — why did cowpox provide immunity? Without germ theory, there was no explanation. Religious groups argued it was wrong to interfere with God’s will by preventing a disease He had sent. Anti-vaccinators feared the idea of putting animal matter (from cows) into human bodies — satirical cartoons showed people growing cow parts after vaccination. When vaccination became compulsory in 1853, the Anti-Vaccination League campaigned against the government forcing it on people, arguing it violated personal liberty.
The Significance of Vaccination
Jenner’s vaccination was hugely significant in both the short and long term:
Short-term: Vaccination saved thousands of lives by preventing smallpox. The government supported it financially, paying Jenner £30,000 in grants. It was made compulsory in 1853, showing growing government involvement in public health.
Long-term: Jenner’s work laid the foundation for all future vaccines. Pasteur built on Jenner’s method when developing vaccines for chicken cholera and rabies in the 1880s. Smallpox was eventually eradicated worldwide in 1980 — the only human disease ever completely eliminated. Jenner is often called the “father of immunology.”
Limitations: Jenner could not explain why vaccination worked (germ theory was not developed until the 1860s). His method only worked for smallpox — it could not be applied to other diseases until Pasteur understood the underlying science. Opposition slowed its adoption, and some people continued to die from smallpox for decades.
Continuity and Change in 18th-Century Medicine
Jenner’s vaccination was a breakthrough, but it is important to see it in context. Most aspects of 18th-century medicine showed continuity with earlier periods rather than dramatic change:
- Treatments — bloodletting, purging, and herbal remedies remained common. Most patients were treated at home by family members.
- Training — medical training was improving but still inconsistent. Many practitioners had little or no formal education.
- Hospitals — new hospitals were being built (including voluntary hospitals funded by charitable donations), but they were still small and could not cope with epidemics.
- Disease causes — miasma theory persisted. Germ theory was still decades away.
Jenner’s vaccination was a turning point in prevention, but 18th-century medicine still showed strong continuity in treatment (bloodletting, purging) and disease explanation (miasma, humours declining but germ theory not yet developed).