Only one disease has been completely eradicated so far - small pox - caused by a virus !
What follows is the story of how humanity did it...
A Virus Humanity Won Over
In 10,000 BCE, a deadly new virus emerged in Northeast Africa, killing indiscriminately and causing a disease we now know as smallpox.
Around 180 AD, Small pox killed an estimated 5.5 million people in the Roman Empire, including the Emperor, and hastened its decline.
Smallpox kept revisiting countries and continents periodically with global migration patterns : China in the 4th century, Europe in the 7th century - and continued to kill millions of people. Generations watched helplessly as their children succumbed to the disease or were disfigured or blinded by it.
The Japanese smallpox epidemic of 735–737 is believed to have killed as much as one-third of Japan's population.
Between 1868 and 1907, there were approximately 4.7 million deaths from smallpox in India.
During the 20th century, it is estimated that smallpox was responsible for 300 million deaths worldwide. For perspective, the flu is supposed to have killed a 100 million people in 2018-2020.
In the early 1950s an estimated 50 million cases of smallpox occurred in the world each year. As recently as 1967, 15 million people contracted small pox and two million died from it that year.
For Centuries, Inoculation was the only cure for Small Pox
Inoculation was likely practiced in Africa, India, China and Turkey long before the 18th century, when it was introduced to Europe. In China, powdered smallpox scabs were blown up the noses of the healthy. People would then develop a mild case of the disease and from then on were immune to it. There are hints of the practice in China from the 10th century.
Inoculation referred to the subcutaneous instillation of smallpox virus into non-immune individuals. The inoculator usually used a lancet wet with fresh matter taken from a ripe pustule of some person who suffered from smallpox. The material was then subcutaneously introduced on the arms or legs of the non-immune person.
There were problems with inoculation though – some percent of the people still died, and some developed syphilis or other disorders due to the contamination that occurred in the procedure.
A self-taught inoculator from Scotland, Notions found success in treating people from at least the late 1780s through a method devised by himself, despite having no formal medical background. His method involved exposing smallpox pus to peat smoke, burying it in the ground with camphor for up to 8 years, and then inserting the matter into a person's skin using a knife, and covering the incision with a cabbage leaf. He was reputed not to have lost a single patient despite inoculating thousands.
Establishing the idea of Vaccination
Edward Jenner, an Englishman, was the first to demonstrate that vaccination offered a reliable defense against smallpox. It was also a reliable defense against other illnesses, such as poliomyelitis, measles, and tetanus, although this was not known in Jenner's lifetime.
It was 1796 before Jenner made the first step in the long process whereby smallpox, the scourge of mankind, would be totally eradicated - he vaccinated a small boy against small pox.
In those years and throughout history, small pox killed 30% of those it infected and left nearly all the rest of its victims disfigured, or blind, or both. Some of its variants killed 100% of those they infected.
Although he received worldwide recognition and many honors, Jenner made no attempt to enrich himself through his discovery. He actually devoted so much time to the cause of vaccination that his private practice and his personal affairs suffered severely.
But his efforts bore fruit and soon most countries in Europe and in Americas had taken up national vaccination programmes around the beginning of the 19th century.
Many scientific discoveries were needed to make large scale vaccinations possible
Until the end of the 19th century, vaccination was performed either directly with vaccine produced on the skin of calves or, particularly in England, with vaccine obtained from the calf but then maintained by arm-to-arm transfer.
At that time, an Englishman, Sydney Copeman, found that vaccine suspended in 50% chemically-pure glycerine and stored under controlled conditions contained very few "extraneous" bacteria and produced satisfactory vaccinations. All vaccinations supplied by the Government were subsequently from Copeman.
In early 1950s, Leslie Collier, an English microbiologist developed a method for producing a heat-stable freeze-dried vaccine in powdered form. The dried vaccine was 100% effective when reconstituted after 6 months storage at 37 °C, allowing it to be transported to, and stored in, remote tropical areas.
Benjamin Rubin, an American microbiologist developed the bifurcated needle. Easy to use with minimum training, cheap to produce, using four times less vaccine than other methods, and repeatedly re-usable after flame sterilization, it was used globally.
The Final Push for Eradicating Small Pox
In Northern Europe a number of countries had eliminated smallpox by 1900, and by 1914, the incidence in most industrialized countries had decreased to comparatively low levels. In the 1950s, a number of control measures were implemented, and smallpox was completely eradicated in Europe and North America.
The first hemisphere-wide effort to eradicate smallpox was made in 1950 by the Pan American Health Organization. The campaign was successful in eliminating smallpox from all countries of the Americas except four.
In 1958 Professor Viktor Zhdanov, Deputy Minister of Health for the USSR, called on the World Health Assembly to undertake a global initiative to eradicate smallpox. At this point, 2 million people were dying from smallpox every year. Overall, the progress towards eradication was disappointing, especially in Africa and in the Indian subcontinent.
In 1966 an international team, the Smallpox Eradication Unit, was formed under the leadership of an American, Donald Henderson, who was trained at the CDC. In 1967, the World Health Organization intensified the global smallpox eradication effort. Under Henderson’s leadership, the WHO established a network of consultants who assisted countries in setting up surveillance and containment activities, which were as crucial as vaccination in containing small pox.
Early on, donations of vaccine were provided primarily by the Soviet Union and the United States, but by 1973, more than 80 percent of all vaccine was produced in developing countries.
Victory – after 3500 years of the first proven disease case !
After two years of intensive searches, what proved to be the last endemic case anywhere in the world occurred in Somalia, in October 1977. A Global Commission for the Certification of Smallpox Eradication chaired by Frank Fenner examined the evidence from, and visited where necessary, all countries where smallpox had been endemic. In December 1979 they concluded that smallpox had been eradicated.
On May 8, 1980, the World Health Assembly announced that the world was free of smallpox and recommended that all countries cease vaccination:
“The world and all its people have won freedom from smallpox, which was the most devastating disease sweeping in epidemic form through many countries since earliest times, leaving death, blindness and disfigurement in its wake”.
The cost of the eradication effort, from 1967 to 1979, was roughly $300 million US dollars. Roughly a third came from the developed world, which had largely eradicated smallpox decades earlier. The United States, the largest contributor to the program, has reportedly recouped that investment every 26 days since in money not spent on (a) vaccinations and (b) the costs of incidence.