Washington described smallpox as a potentially greater threat than "the Sword of the Enemy".⁸ Historically, it killed over a quarter of those infected.⁹ Smallpox was typically transported to 18th-century America via immigrants and enslaved people. Unlike in Europe, the majority of the American population led relatively isolated lives on farms and plantations. Outside of Boston, Philadelphia, and Charleston, there was little chance of getting the disease, and prior to 1747, there were no smallpox epidemics in Virginia.¹⁰

Washington was one of the few Virginians exposed to smallpox prior to the American Revolution. He and his half-brother Lawrence visited Barbados in 1751 to try and ease Lawrence’s tuberculosis. Not long after arriving the brothers visited Lawrence’s uncle, Gedney Clarke. Washington was hesitant to go since Mrs. Clarke was suffering from smallpox. Just a couple weeks later, Washington noted he had been “strongly attacked with the small Pox”.¹¹ For three weeks, Washington was bedridden and treated by local physician Dr. John Lanaham. Washington’s exposure to the disease meant he was immune from smallpox for the rest of his life, which was imperative during the American Revolution.¹² 

Soon after his appointment as commander-in-chief of the Continental Army, Washington encouraged Congress to create a medical department within the army.²¹ He also immediately had to deal with smallpox, which became more widespread during the war. Between 1775 and 1782, the disease killed at least 100,000 people.²² Soldiers arriving from England and Germany frequently brought the virus to America. Moreover, recruits from all over North America joined the Continental Army, and many who had never been exposed to smallpox suddenly were.²³

Within days of taking command of the army, Washington wrote to assure the president of the Continental Congress that he had been "particularly attentive to the least Symptoms of the small Pox," quarantining anyone suspected of having the disease.²⁴ Washington further promised that he would "continue the utmost Vigilance against this most dangerous enemy."²⁵ John Adams wrote his wife, Abigail, that smallpox “has done Us more harm than British armies”.²⁶ Smallpox plagued the Continental Army as well as the civilian population, and epidemics broke out in major cities including Boston and Philadelphia.²⁷

Washington believed in the effectiveness of inoculation and eventually instituted a system where new recruits were inoculated with smallpox immediately upon enlistment.²⁸ Inoculation involved deliberate exposure to smallpox, usually through an incision made on the arm. This still resulted in a case of smallpox, but usually with milder symptoms and a greater chance of survival, with immunity as the end goal. Many in Colonial America opposed inoculation because it could cause an outbreak if the inoculated person was not properly quarantined while ill. Inoculation was heavily regulated and banned outright in some places. Combined with the procedure’s expense, it was a rare practice in America.²⁹

The small pox has made such Head in every Quarter that I find it impossible to keep it from spreading thro’ the whole Army in the natural way. I have therefore determined, not only to innoculate all the Troops now here, that have not had it, but shall order Docr Shippen to innoculate the Recuits as fast as they come in to Philadelphia. They will lose no time, because they will go thro’ the disorder while their cloathing Arms and accoutrements are getting ready.³⁰

- George Washington to John Hancock, 5 February 1777

Washington had a number of serious health scares while president. The first occurred less than two months after his inauguration. Washington described the illness as, “a very large and painful tumor on the protuberance of my thigh—this prevents me from walking or sitting”.³¹ After weeks of treatments, Dr. Samuel Bard and his father, Dr. John Bard, removed Washington’s tumor on June 17, 1789. It took six weeks for the incision site to heal, during which Washington mainly laid on his right side.³² A similar, but milder, tumor reappeared two years later. Thomas Jefferson wrote to James Madison, “The President is indisposed with the same blind tumour, & in the same place, which he had the year before last in New York.”³³

Then, in the spring of 1790, Washington became very ill. This time he was inflicted by influenza and pneumonia, which affected both his hearing and eyesight. At one point, William Maclay reported that Washington had “nearly lost his hearing.”³⁴

On May 16, Theodore Sedgwick noted, “About five oclock in the afternoon yesterday, the physicians disclosed that they had no hopes of his recovery.”³⁵ However, Washington began to sweat overnight, and by morning, the doctors believed he was out of immediate danger. After recovering, Washington wrote the following about his health:

I have already had within less than a year, two severe attacks—the last worse than the first—a third more than probable will put me to sleep with my fathers; at what distance this may be I know not. Within the last twelve months I have undergone more, and severer sickness than thirty preceding years afflicted me with, put it altogether—I have abundant reason however to be thankful that I am so well recovered; though I still feel the remains of the violent affection of my lungs—The cough, pain in my breast, and shortness in breathing not having entirely left me.³⁶