Edward Jenner
The Father of Immunology
In the 18th century, smallpox was a widespread disease that affected people of all social classes. It was a leading cause of death, claiming the lives of about 400,000 people every year. Even those who survived were often left with disfiguring scars, and one-third of them went blind. The disease had fatality rates ranging from 20% to 60%. Infants were hit even harder, with death rates approaching 80% in London and 98% in Berlin during the late 1800s.
At that time, the only way to fight smallpox was through a primitive form of vaccination called inoculation (or variolation). The practice, originated in China and India, involved deliberately infecting a healthy person with the “matter” taken from a patient with a mild form of the disease. However, it was not without risks, as the disease could sometimes become severe and even fatal in the inoculated person. Additionally, the inoculated person could spread the disease to others and act as a source of infection.
Despite the dangers involved, variolation persisted for many centuries because it was the sole method available to safeguard against smallpox. This changed when the brilliant English physician Edward Jenner devised a remarkable solution. Jenner had long been intrigued by stories of dairymaids who, after contracting cowpox, seemed to gain immunity to smallpox. Contemplating this, he realized that cowpox not only shielded against smallpox but could also be deliberately transmitted from one person to another as a means of protection.

Edward Jenner by John Raphael Smith
In May 1796, Edward Jenner discovered Sarah Nelms, a young dairymaid with fresh cowpox sores on her hands and arms. Jenner took material from Nelms’ sores and used it to inoculate an 8-year-old boy named James Phipps. Following the procedure, the boy experienced a mild fever and discomfort in his armpits. Nine days later, he felt cold and had no appetite, but the next day he showed significant improvement. A month later, Jenner inoculated the boy once more, this time using material from a fresh smallpox sore. To Jenner’s relief, no disease developed, leading him to conclude that complete protection had been achieved.
Two years later, Jenner released a booklet titled “An Inquiry Into the Causes and Effects of the Variolae Vaccinae.” He named the procedure vaccination, deriving the term from the Latin word for cow, “vacca,” and cowpox, known as “vaccinia.” When the Inquiry was published, it received a varied response within the medical community.
Jenner traveled to London hoping to find volunteers for vaccination, but three months passed, and he couldn’t find any. However, the popularity of vaccination grew in London, thanks to the efforts of other individuals. One of them was the surgeon Henry Cline, to whom Jenner had provided some of the inoculants. Soon, Drs. George Pearson and William Woodville also started promoting vaccination among their patients.

Jenner performing his first vaccination on James Phipps. By Ernest Board.
Inspired by the growing support, Jenner conducted a countrywide survey to find evidence of resistance to smallpox or variolation among individuals who had contracted cowpox. The survey results validated his theory. Despite some mistakes, controversies, and deceitful practices, vaccination gained quick popularity in England. By the year 1800, it had also spread to most European nations.
In 1800, Dr. John Haygarth sent the vaccine to Benjamin Waterhouse, a physics professor at Harvard University. Waterhouse introduced vaccination in New England and persuaded Thomas Jefferson to try it in Virginia. Jefferson was a strong supporter of Waterhouse and appointed him a vaccine agent in the National Vaccine Institute, an organization created to execute a national vaccination program in the United States.
Despite achieving worldwide recognition and receiving numerous honors, Jenner did not seek to profit from his discovery. Instead, he dedicated an immense amount of time to promoting vaccination, which took a toll on his private practice and personal matters. The remarkable significance of vaccination was publicly recognized in England when, in 1802, the British Parliament awarded Edward Jenner a sum of £10,000. Five years later, Parliament granted him an additional £20,000 as a testament to his invaluable contribution.
Jenner got married and became the father of four children. The family resided in the Chantry House, Berkeley, which later transformed into the Jenner Museum. In the garden, Jenner constructed a small hut known as the “Temple of Vaccinia,” where he administered free vaccinations to the less fortunate.
After experiencing both acclaim and criticism for about a decade, Jenner gradually withdrew from public life and returned to practicing medicine in the countryside of Berkeley. He passed away at the age of 73 from a massive stroke.

“Smallpox is dead!” Front cover of the magazine of the World Health Organization, World Health, May 1980. Design by Peter Davies. © WHO
During the 1950s, significant progress was made in eradicating smallpox from many regions in Europe and North America. However, the disease still persisted, with approximately 15 million cases reported annually, primarily in South America, Africa, and India. The World Health Organization (WHO) took action in 1967, launching a global campaign to eliminate smallpox. The relentless efforts paid off, and in 1977, smallpox was finally eradicated. On May 8, 1980, the World Health Assembly made a historic announcement, declaring the world free from smallpox and recommending the cessation of vaccination in all countries.
The exact number of lives that would have been lost to smallpox since 1980, had the vaccine not been developed, remains uncertain. However, estimates suggest that approximately 5 million lives could have been claimed each year. This implies that between 1980 and 2018, an astounding 150 to 200 million lives have potentially been saved thanks to the vaccine.

Quotes
“I hope that some day the practice of producing cowpox in human beings will spread over the world - when that day comes, there will be no more smallpox.” —Edward Jenner
“Future nations will know by history only that the loathsome smallpox has existed and by you has been extirpated.” —Thomas Jefferson, 1806, in a letter to Edward Jenner
“There is no vaccine against stupidity.” —Albert Einstein
“Scientific literacy is an intellectual vaccine against the claims of charlatans who would exploit ignorance.” —Neil deGrasse Tyson
Recommended books
References

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