Based on archival materials, collected literature and archival articles analysing the clinical course of the disease, the article presents the medical and social course of one of the recent epidemics of smallpox in Europe, which took place in Wrocław in 1963. During the epidemic, 99 people fell ill and seven of them died. The authors describe how a mass vaccination campaign was organised in the city and the entire surrounding region. This historical study shows not only the course of the epidemic itself, but also the ways to prevent and deal with infectious diseases and the organisation of vaccinations in communist Poland. The authors also discuss the issue of the relationship between the vaccination period and the course of smallpox in patients and show the scale of post-vaccination complications in the situation of mass vaccination against smallpox. Although the article refers to historical events, it draws attention to the topicality of challenges posed by the variola virus.