Systems for improving public health and organisations for providing national education were two of the great reforming achievements of 19th-century Britain. Despite the overlapping personnel and historical contemporaneity, scholars have rarely considered the two projects in tandem. This essay shows that developments in public health were at the heart of two foundational moments in the rise of 19th-century mass schooling. The originators of the monitorial system, a method of peer-educating working-class children cheaply that dominated British mass schooling at the turn of the 19th century, were deeply invested in the origin and spread of vaccination. Similarly, the first state teacher training system was conceived by a medical doctor in the 1830s, who first rose to prominence investigating cholera in Manchester earlier in the decade. Using archives of school providers, training institutions and the educational state apparatus, I show that medical prophylactic interventions of vaccination and sanitary reform helped galvanise the government into educational reform, by imagining the working class as pathological and providing templates for their palliation. By showing that the roots of the modern school system were deeply imbricated in attempts to combat smallpox and cholera, both in form and in epistemology, this paper argue that critical medical humanists should consider the role of epidemiological thinking in institutions and disciplines which seem, on first sight, removed from the clinic and the lab.