After the previous three recessions, the vast majority of people who were laid off in the US lost their jobs permanently. Some were essentially replaced by new software or factory robots. In other cases, their employers folded or entered new lines of business.

After those recessions, the unemployment rate took so long to fall back to normal levels that economists began applying a chilling label: “Jobless recoveries.”

If a substantial number of small businesses are forced into bankruptcy, a similar dynamic could emerge this time, economists warn. Most job cuts by small companies in this recession have occurred because the business has shut down, whether by government order or from lack of demand, according to research released this week by the US Federal Reserve and other economists. If those companies can’t reopen, those layoffs will become permanent.

Research by the JPMorgan Chase Institute has found that only half of all small businesses have enough cash on hand to last a month without revenue.

Even after countries around the globe lift closure orders, many consumers will not likely be comfortable.

An eventual vaccine or an effective drug therapy, would make more people more comfortable about returning to venues they used to frequent – returning to airports, shopping, eating out, or attending concerts, movies or sporting events, especially as they used to – as part of tightly seated crowds.

That, in turn, would lead companies to recall more laid-off workers. So, not until the virus is well under control can full economic recoveries happen, economists say.

Call it realism or pessimism, but more employers are coming to a reluctant conclusion: Many of the employees they’ve had to lay off in the face of the pandemic might not be returning to their old jobs anytime soon. Some large companies won’t have enough customers to justify it. And some small businesses will not likely survive at all despite government aid.

In the meantime, structural changes in the economy might help make many temporary layoffs permanent. It’s not clear, for example, when restaurants will need anywhere near as many workers they did before the virus struck, in fact it is not clear how long it will take the travel, tourism and hospitality sectors to bounce back to anything close to the numbers we have taken for granted in recent years.