In 2012 this was in the description of the Twilight, the war the obliterated most of humanity's records in the early 21st century:
"There was a general, yet limited, nuclear
exchange that occurred sometime in the period 2020–2030,"
"Other events during Twilight included a world-wide influenza
epidemic and several other pandemics, especially in the years
following the nuclear exchange. There is considerable evidence
that at least some of these plagues originated in the bio-weapons
labs of one or more of the belligerent nations."
Of course, this scenario is not exactly rare in science-fiction, in fact most sci-fi has some sort of cataclysm that overtakes mid-stage technological civilizations and ends up generating a new age of exploration.
Still, pretty interesting.