Amazon has temporarily closed a New Jersey warehouse after a spike there in asymptomatic COVID-19 cases, a rare move that comes as the company gears up for a final push in what’s widely expected to be a record holiday shopping season.

The world’s largest online retailer told employees at the warehouse in Robbinsville Township that the facility will be shuttered until Dec. 26, a spokesperson confirmed.

Amazon has generally opted to keep its warehouses and other facilities running amid outbreaks, betting that more frequent cleanings and social distancing limit the risk of the virus spreading within a given building. A rare exception came early in the pandemic in March, when an apparel returns warehouse was idled by order of Kentucky Governor Andy Beshear after an outbreak there.

The New Jersey facility, PNE5, is a sortation center that takes finished packages from other Amazon warehouses and routes them to individual post offices and other facilities for so-called last mile delivery. The center serves the Philadelphia and Trenton, N.J., areas, according to MWPVL International, a logistics consulting firm that tracks Amazon’s network.

The temporary loss of one such building is unlikely to seriously strain Amazon’s delivery network, which has plenty of built-in redundancy.

The Seattle giant has spent months ramping up a testing program for its hundreds of thousands of warehouse workers, relying both on third-party labs and its own facilities.

“Through our in-house Covid-19 testing program, we detected an increase in the number of asymptomatic positive cases at our PNE5 facility in northern New Jersey and have pro-actively closed the site until December 26th out of an abundance of caution,” Leah Seay, an Amazon spokesperson, said in an email. “This is exactly why we built the program—to identify asymptomatic cases and ensure that we can take swift action to prevent spread.”

Workers at the facility would be paid for scheduled shifts they miss, she said.

The closing was reported Sunday by CNBC.

Amazon said in October that some 20,000 workers had caught COVID-19 during the pandemic’s first six months, a rare disclosure for a large employer. The company asserted that the rate of infection among its employees was lower than prevailing rates among the general population. But some infectious disease experts said the disclosure lacked key data necessary to evaluate that claim.

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