The Secret History of Vaccines: How an African Slave Paved the Way for Immunization

Vaccines have become a fundamental part of the healthcare industry. We have been using them for decades to prevent infection and ward off disease. In the age of the coronavirus, vaccines are considered our best shot at overcoming the pandemic.

But where did scientists and doctors get the idea to vaccinate patients in the first place? Some vaccines work by infecting the person with a trace amount of the disease in question. Back in the early days of medicine, intentionally infecting someone with a virus was virtually unheard of, until it proved effective.

In reality, the history of vaccines is related to the history of slavery. Learn the surprising truth about the origins of vaccines.

Smallpox Comes Ashore

In the early 1700s, when colonists were returning from Africa with enslaved Africans aboard their ships, they encountered a disturbing surprise when smallpox first appeared in Boston, MA in 1721. With little understanding of infectious disease, many residents started fleeing from the area, afraid the disease would ravage their loved ones. Patients came down with fever, fatigue, and a nasty rash that would leave disfiguring scars. It had a mortality rate of up to 30%.

The outbreak morphed into a full-fledged pandemic as the disease spread like wildfire throughout the colonies, killing hundreds along the way. The message “God have mercy on this house,” was nailed to the door of a house where patients were left to die.

Historian Susan Pryor notes, “Few diseases at this time were as universal or fatal.”

Smallpox eventually made its way to the Native Americans. With no immunity against this strange disease, it ended up killing thousands of natives across what would become known as the United States.

Historians believe smallpox first made its way to the U.S. from Africa. Ripped from the arms of their loved ones, slaves were forced into cramped, unsanitary conditions that likely helped spread the disease. The captives then passed it onto the colonists, leading to one of the deadliest outbreaks in history.

The first enslaved people arrived in Boston in 1638, and by 1700, there were already 1,000 enslaved Africans living in the city.

A Groundbreaking Approach

With few resources to combat infection, doctors were willing to try anything. That’s when an enslaved man known only as Onesimus came forward with an idea that could stop the spread. He spoke of an old technique used in his village in Africa. Residents would rub the puss of infected people into their wounds, which gave them immunity against the disease.

Records show that Onesimus was of West African descent. He was purchased in 1706 by prominent Puritan minister Cotton Mather, who wanted Onesimus for his congregation. Mather felt it was his duty to educate and convert Africans into Christians. He also looked down on their “Devilish rites,” as he called them.

Mather’s private notes reveal that he didn’t trust Onesimus. He described his “thievish” behavior and recorded in his diary that he was “wicked” and “useless.”

Yet, Mather recognized that Onesimus is a “pretty intelligent fellow.” It wasn’t until 1716 that Onesimus told him his secret to defeating smallpox.

He wrote at the time that Onesimus said that he “had undergone an operation, which had given him something of the smallpox and would forever preserve him from it…and whoever had the courage to use it was forever free of the fear of contagion.”

Mather soon started researching the idea. He confirmed these ideas with some of the other slaves, while tracing the technique back to China and Turkey.

He soon traveled the colonies promoting the idea of this so-called inoculation—also known as variolation. However, other white colonists were hesitant to undergo a procedure that was first coined by a black man.

According to historian Ted Widmer, “A local newspaper, called The New England Courant, ridiculed him. An explosive device was thrown through his windows with an angry note. There was an ugly racial element to the anger.”

The approach took on a new life in 1721 when Zabdiel Boylston became the only physician in the area to support variolation. He started inoculating his family members and other residents against smallpox.

Of the 242 people he inoculated, only six died—one in 40, compared to one in seven deaths among the population of Boston who didn’t undergo the procedure.

Overall, the smallpox pandemic killed 844 people in Boston alone, around 14% of the population. However, the medical community had a new tool at its disposal. Towards the end of the century, Edward Jenner developed the world’s first smallpox vaccine using trace amounts of cowpox to activate the body’s immune system. Before long, smallpox vaccines were mandatory in Massachusetts.

It’s not clear what happened to Onesimus. Records show that he partially bought his freedom after buying another enslaved person. History has glossed over the fact that colonists first learned about inoculation from one of their slaves. Edward Jenner is often remembered as “the father of vaccines,” but chances are he wouldn’t have discovered this technique if it weren’t for Onesimus and the legacy of his people.