The Chinese city of Wuhan has conducted more than 400,000 nucleic acids tests within the first three days of a citywide campaign to test all residents for Covid-19, the Wuhan Municipal Health Commission said today.

The testing drive comes after several new local cases were reported this month, sparking concern that the coronavirus could still be spreading in the city of 11 million people, where the virus emerged at the end of last year.

The number of tests conducted daily has also steadily increased from 72,791 on May 14 — when the campaign began — to 222,675 on May 16, local health authorities said.

Who is being tested? The Wuhan government said that the citywide tests will apply to most permanent and temporary residents who were never tested before, and will exclude children under the age of 6.

How will it work? The tests are conducted free of charge, and only those who test positive will be notified by authorities, the local government said. All samples will be stored in a secure and independent server to safeguard privacy, authorities added.

Last Thursday, leading Chinese business publication Caixin reported that Wuhan will carry out the citywide testing in waves. Over a period of 10 days, each district will stagger their tests in an effort to prevent a resurgence of the virus.