You'd see a devaluing of the underlying property, so you'd be upside down on your mortgage. Property owners would stop taking care of buildings in terms of rent

You'd see a devaluing of the underlying property, so you'd be upside down on your mortgage. Property owners would stop taking care of buildings in terms of rentals, so maintenance would be a significant issue. There are a lot of bank loans using a real estate asset as collateral - those would now be significantly riskier for the banks to hold, so new loans would probably stall and/or become more restrictive, slowing growth. Municipal services would start to take a hit next, since a lot of the property taxes go to things like schools and waste disposal. On the flip side, people not paying their rent would have more money in their bank accounts to cover an unforeseen medical bill. I doubt retail would increase by that much if quarantining was still in place, though.