Amazon.com Inc, the world’s largest online retailer, announced on Saturday that its paid time-off policy for employees with COVID-19 will stop on May 2.

The modification was made as a result of the availability of COVID-19 vaccines and new guidelines from the US Centers for Disease Control and Prevention, according to the statement.

Following a verified COVID-19 diagnosis, Amazon employees in the United States will be given five days of unpaid leave, according to a note sent to Reuters by the company.

“We can continue to safely adjust to our pre-COVID policies,” the company said, citing the sustained easing of the pandemic, the availability of vaccines and treatments, and updated public health guidance.

The changes come amid a stream of challenges for Amazon after a recent effort to unionize some warehouses. In April, workers at its warehouse in New York City voted to form the first union.

On Saturday, Amazon said it is halting site-wide notifications of positive cases in facilities, unless required by law, as well as efforts to encourage vaccination.

In January, Amazon trimmed paid leave for workers with the virus to one week, or up to 40 hours. Before that, they got two weeks of paid time off for COVID-19.