Could be. The source of this article is New Scientist and they are wrong more times than they are right.
Variolation wasnt compulsory, but it was highly recommended. The Continual Congress wanted each and every soldier variolated. They were to be vaccinated because of two reasons. The first was that soldiers could easily contract smallpox from each other and from the civilian population. The other reason was that a few people in the Continual Congress were well aware that the British had used smallpox as a weapon previously during the French and Indian War, in 1763. At the PBS web site we discovered a letter from the British Commander-in Chief, Sir Jeffery Amherst: "Could it not be contrived to send smallpox among these disaffected tribes of Indians? We must use every stratagem in our power to reduce them."
In her book, Pox Americana: The Great Smallpox Epidemic of 1775-82, Elizabeth Anne Fenn points out that 130,000 North Americans lost their lives to smallpox. Washington, aware of what the British had done in 1763, decreed that letters from Boston were to be dipped in vinegar to kill the germs. When it became evident that the British were attempting to spread smallpox by invariolating civilians and sending them out among his troops (remember, an invariolated individual was contagious for at least two weeks), he asked the Continental Congress for funds to invariolate his troops.
Appealing to the international public, the Pennsylvania Gazette published, "Lord Cornwallis' attempts to spread the smallpox among the inhabitants in the vicinity of York . . . must render him contemptible in the eyes of every civilized nation."
Some put the death rate to small pox at 25%, while some virulent strains were approaching a 40% rate. Fenn puts the overall rate of death at this time at 30%. Just recently weve learned that there was a childhood form of smallpox, like chicken pox, that wasnt as deadly, but it did produce an immunity to smallpox later in life. However, this childhood smallpox was endemic of Europe and not of the early colonies.