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"Definition of epidemic
1 : affecting or tending to affect a disproportionately large number of individuals within a population, community, or region at the same time"
https://www.merriam-webster.com/dictionary/epidemic

Sounds like @deirdyweirdy is using the word correctly in this context.

that would also include natural disasters like hurricanes and political elections..

I see your point.

We should let Merriam Webster know.