© Getty Images

Inoculation -

Before the first vaccine was invented there was an immunization procedure known as inoculation or variolation. Researchers say that the first written inoculation procedure dates back to 1549.

© Shutterstock

Oral tradition of inoculation -

There are versions of an earlier inoculation practice, but it's only recorded in oral history. It's said that inoculation was invented by a Taoist or Buddhist monk or even a nun.

© Getty Images

Spread to the Ottoman Empire -

In the 1500s, the practice of inoculation traveled west toward the Ottoman Empire and reached Constantinople (modern-day Istanbul, Turkey) in the mid-1600s.

© Public Domain

Inoculation in Europe and North Africa -

After this, inoculation made its way to Europe and North Africa, and finally to the Massachusetts colony through a slave named Onesimus.

© Shutterstock

Cotton Mather’s role -

Onesimus told Reverend Cotton Mather, known for his role in the Salem Witch trials, that he had been inoculated by those who enslaved him so he wouldn't catch smallpox and would therefore be worth more when sold.

© Getty Images

Lady Mary Wortley Montague -

Lady Mary Wortley Montague was a British socialite who lived in Constantinople. She had her son and daughter inoculated. By 1723, it was obvious that inoculation in a controlled setting and with a medical professional's supervision was better than simply catching the illness.

© Getty Images

Benjamin Franklin and inoculation -

Following the death of his son, Benjamin Franklin became an advocate of inoculation. He wrote several book introductions, and in 1759, even provided numbers that proved the risk of death was lower if you were inoculated. 

© Getty Images

George Washington and smallpox -

During the American Revolutionary War, General George Washington demanded that the American troops be inoculated in order to join the Continental Army.

© Getty Images

Edward Jenner’s cowpox discovery -

Edward Jenner observed that milkmaids and those who had already been infected with cowpox were immune to smallpox.

© Getty Images

Jenner’s experimentation -

The first official vaccine was administered in the late 1700s when Edward Jenner inoculated a person who had never had smallpox or cowpox. The subjects in this experiment reacted mildly to the cowpox, which was given first, but had no reaction to the smallpox inoculation afterward. 

© Getty Images

The role of Louis Pasteur -

For about 80 years, the cowpox vaccination was the only solution for preventing smallpox. A person known as Louis Pasteur, a French biochemist was one of the prominent people scientists interested in disease-causing organisms.

© Getty Images

Pasteur’s attenuation process -

Rabies was also a problem during this time and  Pasteur theorizes that something in the saliva of the animals was transferable. He first tried giving a small dose of rabies to animals but it was unsuccessful. He then decided to try and weaken the infectious agent before giving it to someone.

© Getty Images

The case of Joseph Meister -

Louis Pasteur experimented with drying the brains and spinal cords of rabid rabbits to weaken the rabies virus, eventually developing a vaccine using this method. He tested the vaccine on Joseph Meister, a young man bitten by a rabid animal, saving his life after he showed no symptoms of rabies.

© Getty Images

The success of Pasteur’s vaccine -

The success of Pasteur's vaccine marked a significant leap in vaccination technology, demonstrating the effectiveness of attenuated viruses. This principle of weakening pathogens to create vaccines became foundational for many future vaccines developed at the Pasteur Institute.

© Shutterstock

Development of toxoid vaccines -

In the 1800s, scientists discovered antibodies—proteins that bind to and inactivate pathogens critical for preventing disease. This led to the development of antitoxins, where antibodies were produced in bulk and given to people to boost their immunity while their bodies developed their own antibodies.

© Shutterstock

The origin of antitoxins -

Antitoxins were created when a toxin from tetanus or diphtheria was given to a large mammal such as a horse. Once the animal developed antibodies against the toxin, they were harvested, purified, and given to humans.

© Shutterstock

The FDA’s formation -

In 1902, after an antitoxin led to several deaths, the United States federal government created what's now known as the Food and Drug Administration. It was the first step in regulating medicines and therapies.

© Shutterstock

The rise of toxoid vaccines -

In the 1920s, it was discovered that, if combined with a toxin, an antitoxin would inactivate the toxin while leaving enough for the human immune system to react against it. 

© Shutterstock

Electron microscopy and viral research -

In the 1930s, the development of electron microscopy revolutionized virology by allowing scientists to directly observe and classify individual viral particles based on their shape and size.

© Getty Images

Advances in virology and vaccine development -

This breakthrough led to rapid viral research, aiding in the creation of vaccines for influenza, polio, and other critical viruses.

© Getty Images

Polio vaccine development -

By 1954, Jonas Salk had created the first killed virus vaccine, or inactive vaccine, which was used to prevent Polio. 

© Getty Images

The oral polio vaccine -

In the 1960s came the oral polio vaccine. At this point in history, trust in vaccines had been eroded. Albert Sabin developed the oral vaccine and brought it from the Soviet Union and Latin America to the USA.

© Getty Images

Polio eradication efforts -

By the early 2000s, polio had been eliminated in Europe, the Americas, and most of Asia. In 2010, there were outbreaks in Africa and Central Asia. However, by the 2020s, type 2 and 3 polio had been eradicated, and only type 1 was present in Central Asia.

© Shutterstock

Smallpox eradication -

In the 1950s and '60s, cooperation among nations led to the eradication of smallpox.

© Getty Images

Scientific leaps in vaccine technology -

Advances in microbiology led to the development of subunit vaccines, where surface proteins of pathogens alone could trigger immunity. Later, recombinant vaccine technology was developed, using genetic material to create proteins in labs, avoiding pathogen cultivation and thereby improving safety.

© Shutterstock

COVID-19 and vaccine development -

In late 2019, a novel coronavirus emerged in Wuhan, China, leading to the COVID-19 pandemic. Governments worldwide invested in vaccines, with Sinovac (killed virus) and Sputnik V (adenovirus vector) announced by mid-2020.

© Shutterstock

COVID-19 -

Pfizer and Moderna developed mRNA vaccines, approved in December 2020, using lipid nanoparticles to deliver genetic material. These vaccines trained immune cells to produce and recognize coronavirus proteins, enabling T cells and B cells to combat infection and provide long-term immunity.

Sources: (The College of Physicians of Philadelphia)

See also: Interesting facts about immunization

© Shutterstock