The epidemic has upended traditional face-to-face working practices, with millions of employees at least temporarily based at home in businesses that have been able to make the switch to curb exposure to the potentially deadly virus.

The Conference Board report said 77% of respondents in the April 15-28 survey expect more employees to work from home more than three days a week, with information technology and financial services, already areas with the highest remote working rates, set to lead the way.

Tech giants such as Alphabet Inc’s Google, Facebook Inc and Twitter Inc have said they would allow most employees to work remotely until the end of the year.

Less than one in 10 businesses polled said more than 20% of their full-time employees worked from home before the epidemic.

Businesses with at least 10% of their staff working from home before the epidemic were more likely to self-report productivity gains over the past several weeks, the survey also showed.

A widespread shift to more teleworking would likely reshape the fabric of cities. With fewer commuters, major transit systems would lose revenue, and spending on city center food services, retail and other services would drop.

Of the 152 HR executives in U.S.-based organizations surveyed, more than 60% of respondents were in the business and professional services, manufacturing and health care sectors.

(Reporting by Lindsay Dunsmuir; Editing by Richard Chang)