Protesters across the nation have been speaking out against vaccine mandates, but historians say they are deeply rooted in the country’s beginnings.

Andrew Wehrman, a medical historian of Central Michigan University, says the United States owes its independence partially to a vaccine mandate for smallpox.

In 1777, a smallpox outbreak devastated the Continental Army under Gen. George Washington’s command. The loss of soldiers from the disease threatened defeat to Great Britain during the American Revolution.

Washington ordered a vaccine mandate for his troops and very few soldiers got sick from smallpox afterward.

“Americans were calling on each other to come together in a common cause against Great Britain,” Wehrman says. “The need for mass immunization was forged in the same fire as the Revolution, a need for common good.”

In the decades following, mandates became more common as did resistance from a small minority of Americans.

Wehrman says the history of vaccine mandates show that they do work to combat diseases.

Doctors agree as many workplaces are starting to require employees to receive the COVID-19 vaccine or face being fired.

“There’s a history of effectiveness and certainly a history through mandates of essentially eliminating certain diseases from being part of our everyday life,” says Dr. John D’Angelo of Northwell Health.

Wehrman’s research on the history of inoculation in early America will be published in a book next fall.