From the (recent) archives, a Lars Jonung and Werner Roeger report on behalf of the European Union's Directorate-General for Economic and Financial Affairs: The Macroeconomic Effects of a Pandemic in Europe (June 2006).
A brief cherry-picked quote:
"In our baseline scenario we find for the first year of a pandemic, that is for 2006, a supply effect of - 1.1 per cent of GDP and a demand effect of -0.5 per cent, totalling a fall in GDP of - 1.6 per cent. These effects diminish sharply for 2007 and 2008 but a long-run negative effect of - 0.6 per cent remains due to the reduction in the labour force caused by the pandemic. Additional effects can be added to this scenario. If we do so, we end up with an estimate of the GDP loss ranging between 2 and 4 per cent.
Still, such a pandemic does not have to spell economic disaster for Europe. The macroeconomic effects of a future pandemic as estimated here are roughly of the same size as those of a major recession."
If there is already a "major recession" underway all bets are off.