Historical analysis of the first smallpox vaccination campaigns in early 19-century northern Italy: organisation and communication insights for contemporary epidemics' prevention and control

Background: In the annals of public health, smallpox is a watershed, being the first disease eradicated by vaccination. Drawing parallels to contemporary pandemic control measures, we examined the first smallpox vaccination campaigns in early 19th-century northern Italy and the seminal work of Luigi Sacco. Our study delves into this under-explored historical landscape to elucidate lessons that resonate with modern public health dilemmas. Methods: We scrutinised primary sources from the Historical Civic Archive of Pavia, the State Archive of Pavia, and the State Archive of Milan. These archives provided exhaustive data on administrative decrees, local epidemiology, and university-health authority collaborations. Using period-specific keyword searches and expert consultations, we extensively reviewed correspondence, vaccination lists, and academic writings, including Luigi Sacco's seminal Trattato di vaccinazione. The epidemiological investigation focused on the pivotal period of 1816–1828 in Lombardy's 19th-century public health landscape. Results: Organisational reforms enacted in 1821 succeeded in doubling the number of vaccinations administered in Pavia, stabilising at elevated rates in subsequent years. Despite improvements, incongruities in epidemiological data and vaccinator remuneration persisted. Communication strategies pioneered by Sacco, encompassing academic and religious collaborations, demonstrated their efficacy. Epidemiological data revealed an initial surge in vaccination uptake in 1822, with a declining trend in the following years, notably impacted by logistical and data recording limitations. Conclusion: Our research underscores three salient dimensions pertinent to contemporary public health paradigms: first, the vital function of local administrative bodies as efficacious service providers, immunisation register keepers, and social safety nets; second, the equilibrium between mandatory vaccination policies and discretionary enforcement as a pragmatic framework for public compliance; lastly, the irrefutable importance of credible communication strategies in fighting vaccine hesitancy. These insights are not merely historical curiosities but cardinal principles for effectively managing modern epidemics and infectious disease threats.