Amazon says close to 20,000 of its staff have tested positive for coronavirus or are presumed to have had covid-19, as it seeks to dispel concerns over workforce safety and a lack of transparency over outbreaks.

The ecommerce platform said on thursday that, following a study of all of its nearly 1.4m amazon and whole foods frontline workers in the us between march and mid-september, it had found 19,816 were positive or presumed positive.

According to the companys analysis, this was 42 per cent lower than the expected infection rate, which was calculated based on the general population rate adjusted for the geography and age of its staff.

An amazon spokesperson said that the numbers refer to amazon and whole foods warehouse and cashier staff, not delivery drivers, who are contractors.

Amazon has benefited from huge demand during the coronavirus pandemic, with profits doubling in its second quarter. but the platform has come under fire from staff and politicians for not doing enough to protect frontline workers from the virus and, until now, for declining to share full data on outbreaks in its warehouses.

In may, 13 state attorneys sent a letter to jeff bezos, amazons chief executive, and john mackey, the head of whole foods, calling for a state-by-state breakdown of data for both companies. workers have also petitioned for amazon to improve its working conditions during the pandemic.

Since march, workers and their communities have been demanding these numbers from amazon, said dania rajendra, director of workers group athena.

Now we know why the corporation refused: amazon allowed covid-19 to spread like wildfire in its facilities, risking the health of tens of thousands of people who work at amazon as well as their family members, neighbours and friends. amazon is, in no uncertain terms, a threat to public health.

The analysis published on thursday was conservative, amazon said, adding that a positive test does not mean someone became infected as a result of their employment with amazon these individuals can be exposed in many ways outside of work.

The company added that it would increase in-work screening from thousands of tests a day to 50,000 a day by november across 650 sites.

It also said that it had been able to lower the likelihood a worker would have to quarantine through enhanced social distancing measures and video-based contact tracing at its sites.