The illness debilitates its victims for weeks, inflicting massive damage on society, though it is only fatal in a third of a percent of infection cases. The pandemic is curtailed when a vaccine becomes available.
The virus kills 19-25 million people worldwide, in different variants of the scenario.
The world loses between $7 trillion and $17 trillion of GDP over five years, almost as severe as the Global Financial Crisis of 2007-2012. In financial markets, equities are badly hit. A typical investment portfolio suffers negative returns. Long term bond markets suffer, notably in the Eurozone and UK.