I'm starting to wonder if monkeypox was always a real threat for wide spread in principle, but it never did because the global population was, coincidentally, l

I'm starting to wonder if monkeypox was always a real threat for wide spread in principle, but it never did because the global population was, coincidentally, largely immune to it because of widespread smallpox vaccination. A paper from 2010 suggests that the outbreaks in Nigeria started around the time when herd immunity from the last smallpox vaccination campaigns in the area (1980s) would be substantially fading, with the majority of the population not immunized, having been born after: > Factors associated with increased risk of infection included: living in forested areas, male gender, age < 15, and no prior smallpox vaccination. Vaccinated persons had a 5.2-fold lower risk of monkeypox than unvaccinated persons (0.78 vs. 4.05 per 10,000). Comparison of active surveillance data in the same health zone from the 1980s (0.72 per 10,000) and 2006–07 (14.42 per 10,000) suggests a 20-fold increase in human monkeypox incidence. > [...] > More than 90% of cases identified in our surveillance program were born after mass smallpox vaccination campaigns officially ceased, and less than 4% of infected individuals had evidence of previous smallpox vaccination. Furthermore, our data suggest that vaccine-induced immunity is long lasting because individuals who were vaccinated against smallpox over 25 y ago still appear to be at significantly reduced risk of monkeypox. https://www.pnas.org/doi/10.1073/pnas.1005769107 https://www.pnas.org/doi/10.1073/pnas.1005769107