Testing for Covid-19 infections and a fast turnaround for results are critical for controlling the pandemic, but broad-based population tests are not always useful, Reuters quoted officials at the World Health Organisation as saying on Thursday.

Maria Van Kerkhove, a WHO epidemiologist, said the UN agency recommended suspected cases be tested and their contacts, if feasible, likewise, but the focus should be on people with symptoms.

Mike Ryan, head of its emergencies programme, noted that broad population testing programmes absorbed a large amount of resources.