Pox Americana follows the smallpox epidemic that spread through North America from 1775-1782, tracing its impact on the Revolutionary War and Native American and Colonial society. Historian Elizabeth Fenn is meticulous in chronicling the devastation, using firsthand accounts and surviving records to sketch out the death and fear that followed the disease.

The impact of smallpox on the Revolutionary War occupies much of the book. Epidemiologically, the Americans were at a disadvantage. Smallpox was endemic in Europe, and British soldiers were much more likely to have been exposed to the disease, gaining immunity. This vulnerability led to serious losses during the revolutionary army’s invasion of Canada, as smallpox weakened and killed susceptible soldiers.

George Washington struggled with the decision of whether to inoculate his soldiers. Under the imperfect technique of the time, inoculation was a draining affair, confining inoculees to sickbeds. The process also potentially increased the risks of transmission, as inoculees were contagious during the dormant period that followed inoculation. Fenn skillfully uses this dilemma to build tension in a historic account.

In the post-Revolutionary period, Fenn focuses on the impact of smallpox on Native American populations throughout the continent, offering repeated accounts of decimated villages and devastated cultures. Native peoples were more vulnerable to the disease, and the successive accounts of loss are heart-rending.

The book is thorough and engaging but can be technical in its presentation of history. The larger themes of the Revolutionary War aren’t fleshed out. The author, it seems, is confident that readers will remember battles and developments they may not have encountered since elementary school. But the book is compelling in advancing its central theme: the outsized impact of this continent-wide epidemic.