History of Vaccines (Part 1)

Part 1: Early Days

In this four-part series, we look at the history of vaccination and how it has shaped public health

While the story of modern immunisation begins with Edward Jenner’s smallpox vaccine in 1796, the principle of conferring immunity by exposure to antigens had been part of medical lore for centuries.

Several cultures had experimented with ‘variolation’ with some success, although its downsides had helped breed considerable scepticism. The process, which takes its name from Variola (smallpox), involved deliberately infecting an individual with the virus in order to induce immunity.

Early references to inoculation can be traced back as far as the Chinese Liao Dynasty around the 10th century where the son of a statesman was said to have been inoculated against smallpox by having a powder made from smallpox scabs blown up his nose. Inoculation was also achieved by scratching smallpox into the skin.

The scourge of smallpox relentlessly tore through the second millennium, killing millions across the globe. Epidemics of whooping cough, measles, yellow fever and other lethal infectious diseases emphasised the need to tackle contagious illnesses but science was a long way from providing an answer.

The age of exploration offered new opportunities for viruses such as smallpox as global travel took off. The Portuguese sparked a smallpox epidemic in India in 1545; French Jesuits inadvertently wiped out Native American tribes in Canada in 1625; while streams of early settlers in the US introduced a series of deadly diseases to their adopted homeland.

Meanwhile, in China, the Chinese Emperor K’ang succeeded to the throne in 1661 after his father had died of smallpox and became an advocate of inoculation. He wrote:

“In the beginning, when I had it tested on one or two people, some old women taxed me with extravagance, and spoke very strongly against inoculation. The courage which I summoned up to insist on its practice has saved the lives and health of millions of men. This is an extremely important thing, of which I am very proud.”

Around the same time, variolation was established in some parts of Africa and began gaining ground in Europe. Lady Mary Montagu (1689-1762), whose husband was ambassador to Turkey, had her son variolated in Constantinople. She told a friend:

“I am going to tell you a thing that I am sure will make you wish yourself here. The small-pox, so fatal, and so general amongst us, is here entirely harmless by the invention of ingrafting, which is the term they give it.”

Montagu wrote of the Turkish practice of annual inoculation against smallpox, typically performed by old women each autumn. Thousands of people would have small pieces of infectious tissue rubbed on their skin or injected into their veins and would subsequently be immune from the disease itself, she said.

So impressed was Montagu with this method that she vowed to promote it in England, urging doctors to join her campaign. The practice spread quickly in England and also became popular in the US where it became clear that variolated individuals suffered less severely during epidemics.

A pamphlet written by English physician William Heberden, at the suggestion of Benjamin Franklin, encouraged parents to inoculate their children against smallpox and gave instructions on how to do it. The pamphlet was circulated on both sides of the Atlantic for free and featured an introduction by Franklin which detailed the success of variolation in Boston.

However, variolation was an inexact science. Variolated individuals could still pass the virus to others and some of those inoculated died of smallpox. Still, for all its imperfection, it was the best method available at the time and it prepared the way for what was to follow, Jenner’s breakthrough.

The history of vaccination does not belong to smallpox alone. Understanding the principles of infectious diseases was central to preventing their spread. When Francis Home, a Scottish doctor, transmitted measles from infected patients to healthy people via blood it showed an infectious agent was behind the illness. The mechanism of disease was slowly coming into focus.

As medical science advanced, some even dared to dream of eradication. Dr Matthew Maty, a doctor and librarian wrote in 1767:

“When once all the adults susceptible of the infection should either have received it or be dead without suffering from it, the very want of variolous matter would put a stop to both the natural and artificial smallpox. Inoculation would then cease to be necessary, and therefore be laid aside.”

It would take more than two centuries and some giant leaps forward in immunisation before eradication of smallpox would be achieved, but by the 18th century momentum had gathered behind the principle of inoculation and understanding of disease mechanisms was deepening. The time was ripe for a breakthrough.

Sources:
www.historyofvaccines.org
Ian Glynn and Jenifer Glynn, The Life and Death of Smallpox
Matthew Maty, The Advantages of Early Inoculation
Michael B. A Oldstone, Viruses, Plagues, & History

This series of articles is part of Vaccines Today’s efforts to raise awareness of European Immunization Week 2011 which runs from 23-30 April