Monkeypox Emergence and the Eradication of Smallpox: An Historical Review.

This article focuses on the epidemiology of human monkeypox in relation to the Global Smallpox Eradication Program (GSEP) and the impact of smallpox vaccination cessation on monkeypox incidence. Human monkeypox, an orthopoxvirus infection with small rodents as its natural reservoir and humans and primates as incidental hosts, was first identified in 1970 in Africa. Smallpox vaccination provided long-lasting cross-protection against monkeypox, contributing to low monkeypox incidence during and shortly after the GSEP (1967–1979). However, surveillance in the Democratic Republic of the Congo (DRC) from 2005 to 2007 showed a 20-fold increase in monkeypox cases compared to the 1980s, correlating with the end of routine smallpox vaccination. The article also notes the 2022 multinational monkeypox outbreak, highlighting the use of smallpox vaccines for prophylaxis and the challenges posed by the virus’s animal reservoir, which makes eradication unlikely.