Virchow was one of the first to identify medicine as a social science. He developed a theory of epidemics that emphasized the social circumstances permitting spread of illness. This approach has been called sociological epidemiology. Virchow began this approach in this study of the 1848 typhus epidemic in Upper Silesia  He also applied similar perspectives to a cholera epidemic in Berlin and to an outbreak of tuberculosis in Berlin during 1848 and 1849.

Virchow's analysis of the epidemic emphasized the economic, social, and cultural factors involved, and clearly identified the contradictory social forces that prevented any simple solution. Instead of recommending medical changes such as more doctors or hospitals, he outlined a revolutionary program of social reconstruction, including full employment, higher wages, the establishment of agricultural cooperatives, universal education, and the disestablishment of the Catholic Church.

"For this research, Virchow argued that defects of society formed a necessary condition for the emergence of epidemics. Virchow classified certain disease entities as “crowd diseases" or "artificial diseases"; these included typhus, scurvy, tuberculosis, leprosy, cholera, relapsing fever and some mental disorders. According to this analysis, inadequate social conditions increased the population's susceptibility to climate, infectious agents and other specific causal factors - none of which alone was sufficient to produce an epidemic. For the prevention and eradication of epidemics, social change was as important as medical intervention, if not more so: "The improvement of medicine would eventually prolong human life, but improvement of social conditions could achieve this result even more rapidly and successfully."⁸ Health workers deluded themselves to think that effects within the medical sphere alone would ameliorate these problems. The advocacy of social solutions thus became the necessary complement of clinical work.

"The social contradictions that Virchow emphasized most strongly were those of class structure. For example, he noted that morbidity and mortality rates, and especially infant mortality rates, were much higher in working-class districts of cities than in wealthier areas. As documentation he used the statistics that Engels cited⁷ as well as data he gathered for German cities. Describing inadequate housing, nutrition and clothing, Virchow criticized the apathy of government officials for ignoring these root causes of illness. Virchow expressed his outrage about class conditions most forcefully in his discussion of epidemics like the cholera outbreak in Berlin:

Is it not clear that our struggle is a social one, that our job is not to write instructions to upset the consumers of melons and salmon, of cakes and ice cream, in short, the comfortable bourgeoisie, but is to create institutions to protect the poor, who have no soft bread, no good meat, no warm clothing, and no bed, and who through their work cannot subsist on rice soup and camomile tea... ? May the rich remember during the winter, when they sit in front of their hot stoves and give Christmas apples to their little ones, that the ship hands who brought the coal and the apples died from cholera. It is so sad that thousands always must die in misery, so that a few hundred may live well.

"For Virchow, the deprivations of working-class life created a susceptibility to disease. When infectious organisms, climatic changes, famine or other causal factors were present, disease occurred in individuals and spread rapidly through the community. ...(Waitzkin, H. "Classics in Social Medicine. One and a half centuries of forgetting and rediscovering: Virchow's lasting contributions to social medicine," Social medicine 1 (2006) Digital text available from socialmedicine.info at this link.

Digital facsimile from the Internet Archive at this link. Translated into English by L. J. Rather in Virchow, Collected papers on epidemiology and public health I (1985) 205-319.