MSJAMA. The physicians' dilemma in the 18th-century French smallpox debate.

EVER SINCE THE INTRODUCTION OF THE SMALLPOX INOCULAtion in 18th-century Europe, physicians and patients alike have grappled with questions of individual risk, public health ramifications, and balancing the interests of the individual and the state. Adoption of such a preemptive measure rested historically on a calculation of risk fraught with unknowns and uncertainties; eg, risk of infection vs risk of prophylaxis. In spite of mathematical demonstration of the safety and efficacy of inoculation for the community as a whole, public trepidation prevented its general acceptance in 18thcentury France, highlighting the sometimes divergent interests of the individual and the state. A new form of medical knowledge—the statistical assessment of risk—emerged from the 18th-century French smallpox inoculation debate. After almost 2 decades of limited success in persuading the French to inoculate by highlighting the procedure’s successful practice in Turkey, China, and England, the philosophes, the leading philosophical, political, and social writers of the French Enlightenment, made a mathematical argument for inoculation. In April 1760, Daniel Bernoulli offered France’s Royal Academy of Sciences the first mathematical theory of the propagation of an infectious disease. Convinced that mathematics provided normative evidence that would compel individuals to inoculate, Bernoulli developed formulas for the propagation of smallpox and for the benefit that universal inoculation would provide. He concluded that the universal practice of inoculation would increase life expectancy at birth by 2 years and 2 months. Given the net benefit that inoculation afforded the individual and society, Bernoulli posited that rational individuals would inoculate, despite the 1-in-200 risk of perishing from the procedure. Yet much to the surprise of Bernoulli and his fellow philosophes, the French continued to eschew inoculation. In his 1767 book, New Reflections on the Practice of Inoculation, the Italian physician Angelo Gatti captured what had, for 2 decades, thwarted Bernoulli’s and the philosophes’ efforts to promote voluntary adoption of inoculation. Gatti argued that without complete assurance of its safety, inoculation would never be widely practiced. The inoculation decision entailed a calculation of risk—the guaranteed risk of a mild case of inoculation-induced smallpox in the near term vs the uncertain probability of contracting natural, more virulent smallpox in the future. Challenging the philosophes, Gatti contended that individuals did not view medical risk through the lens of mathematical calculation. Echoing the arguments of the encyclopedist Jean le Rond d’Alembert, Gatti emphasized the paramount influence of the individual’s subjective, psychological experience. The risk of death in the short-term from the inoculation had a paralyzing psychological effect. Gatti wrote, “An immediate risk, no matter how slight, will always make a greater impression than a very great, but distant and uncertain one.” Concerned primarily with self-preservation, no individual wished to be the 1 in 200 to perish from the inoculation. In practice, Gatti argued, people evaluated inoculation based not on statistics but on perception of its costs and benefits, the value one placed on one’s own life, and the quality and type of life to which one aspired. Although the French medical community had not led proinoculation efforts in the 1750s, by the 1760s, the corporation of physicians was perceived as the sole entity capable of persuading the public to inoculate. Inoculation advocate Père d’Entrecolles wrote, “The public awaits . . . the competition between the luminaries [in the Faculté de Médecine]; its decision without a doubt will put an end to all the disputes that have been raised concerning [inoculation.]” The philosophes believed the medical community could quell the psychological, subjective concerns that impeded inoculation by attesting to inoculation’s safety and efficacy. Yet the French medical establishment was hardly a natural ally of the philosophes. The procedure necessitated a shift in physicians’ conceptions of their role, rendering them purveyors of disease as well as healers, since inoculation entailed introducing viral matter from the pus of a virulent smallpox. Within 7 to 10 days, the inoculee fell ill with a mild form of the disease. Moreover, physicians acted cautiously, cognizant of their limited understanding of smallpox’s etiology and the inoculation’s impact. Into the 1770s, physicians expressed concern as to whether inoculation provided lifelong protection against contracting smallpox, whether inoculees spread natural smallpox, and whether inoculation-induced smallpox (known in the 18th century as “artificial smallpox”) was less virulent than natural smallpox. Simultaneously, physicians faced a demanding and emotionally charged public who labeled as “murderers” those who lost patients to inoculation and yet accused physicians who refused to inoculate of complicity in thousands of deaths. The public’s demand for action in a situation in which the public good was poorly defined placed tremendous pressure on the deliberative, consensus-oriented culture of the 18th-century French medical guild. A severe, protracted, Parisian smallpox epidemic in the winter of 1762-1763 forced the French medical community to the forefront of the inoculation debate. France’s leading court, the Parlement de Paris, issued an order halting the practice of inoculation and requesting that the Paris Faculty of Medicine rule on its efficacy and safety. The Parlement’s response to public perception that inoculation had contributed to the outbreak’s severity galvanized the medi-