As Wuhan, the Chinese city where the Covid-19 pandemic began, revs up a massive testing campaign, some residents crowding the test centres have expressed concern that the very act of getting tested could expose them to the coronavirus.

“Some people have expressed worry in the (social media) groups about the tests, which require people to cluster, and whether there’s any infection risk,” Reuters quoted a Wuhan resident as saying.

The unprecedented scale of testing indicates the official level of concern, some experts say. Others say it is an extremely costly exercise and question its effectiveness.