Earlier quoted context omitted.
It's not completely without precedent, in that the 1918 flu pandemic was only a century ago. We don't have a ton of good data, but some researchers are looking at its effects in the US: https://www.bloomberg.com/news/articles/2020-03-27/pandemic-... But I do agree 100% with taken current economic estimates with a huge brain of salt, as our economic machine is far different from the past.
Were virtually all businesses shut down for weeks or months during the 1918 flu pandemic? All I can find is reports of localized shutdowns in certain cities. If not, I don't think you can say it's comparable.
that's the (over-)reaction. the precedent is the more-virulent-than-usual infectious disease. the precedent is the need to break the infection chain to slow/stop the pandemic.
you wouldn't expect the reaction to be 'comparable' after 100 years. you'd hope that we'd have developed methods to better assuage fear and panic though.