Is there a cycle of modern pandemic?

In the beginning of 20^th century the Modern Period achieved a point of linking among countries all over the world that never had before, mainly after the flights became easier.

So, in 1918 it happened the Spanish flu.

Now, in 2020 we have the Covid-19.

The physician and historian Mirko Grmek proposed the concept of “pathocenosis”. This concept is about spatial and temporal evolution of diseases associated to other factors.

Before and between these two pandemics there were others. But maybe not with some kind of similarities of these two inside a kind of pendulum of time around a “pathocenotic” century cycle.