Some American companies say they could lose as much as half their annual revenue from China if the coronavirus epidemic extends through the summer, as businesses struggle to get boots back on the ground amid travel restrictions and shortages of basic protective gear.

Nearly half of U.S. companies in China said they expect revenue to decrease this year if business can’t return to normal by the end of April, according to a survey conducted Feb. 17 to 20 by the American Chamber of Commerce in China, or AmCham, to which 169 member companies responded. One fifth of respondents said 2020 revenue from China would decline more than 50% if the epidemic continues through Aug. 30.

Work-from-home policies had been implemented by 94% of the responding companies, but businesses that require workers on-site said travel restrictions had created burdensome delays.

On Tuesday, China imposed restrictions on travelers arriving from abroad, requiring quarantines for those traveling from outside the country amid rising infections in Europe, South Korea and Japan.

American companies cited global travel disruption as their biggest obstacle to business and said reduced productivity and employees’ inability to get to work are among their greatest challenges. Inside China, travel-restriction policies and mandatory quarantines aimed at preventing the spread of the virus have left many migrant workers homebound even as China tries to restart its labor force.