“We’re recognising how formidable this enemy is that it is quite infectious and quite deadly. And really, the more we learn about it, the more fearsome it appears.”

Frieden’s warning echoed similar messaging by the World Health Organisation (WHO), which held a press conference from Geneva earlier on Monday.

Frieden, who is now president of Resolve to Save Lives, an initiative aimed at countering epidemics worldwide, made his comments as a debate swells within the US government over whether social distancing restrictions that have closed many small businesses will be able to end next month. Current federal guidelines have the restrictions in place until April 30.

Coronavirus latest: US outbreak ‘nearing peak’, Italy’s curve flattens

With a Covid-19 vaccine “at least a year away”, and mobile apps still limited in how much they can help, Frieden said, the US government should create a “coronavirus contact corps” along the lines of the Civilian Conservation Corps that the federal government created during the Great Depression in the 1930s, drawing in many of the millions now jobless because of the pandemic.

Frieden also downplayed the role that tech solutions could play in bringing the pandemic to an end, emphasising that aggressive testing, self-isolation of anyone with any symptoms, quarantine and efforts to make quarantine facilities available, will be crucial in bringing the spread of Covid-19 under control.

Asked whether tech solutions were the primary factor in Singapore’s early success in containing Covid-19, Frieden said: “I’ve seen in the media [people quoted as saying], ‘Look that’s what Singapore did’. No, actually it isn’t.”

“Singapore used traditional contact tracing,” he said. “They have a new app called TraceTogether that has just launched a couple of weeks ago after they successfully controlled infections, that may be helpful. We’ll see.”

“The way down is much slower than the way up,” WHO chief Tedros Adhanom Ghebreyesus said in Geneva on Monday, referring to the contagion’s epidemic curve. “That means control measures must be lifted slowly and with control — it cannot happen all at once. Control measures can only be lifted if the right public health measures are in place, including significant capacity for contact tracing.”

Frieden also criticised the way the department he previously helmed has been sidelined in terms of direct communication with Americans.

Regular CDC press briefings have been halted since shortly after Dr Nancy Messonnier, director of the CDC’s National Centre for Immunisation and Respiratory Diseases, said on February 25 that: “We expect we will see community spread in this country.”

“It’s not so much a question of if this will happen any more, but the rather more correct question to be asking is, ‘When this will happen and how many people in this country will have severe illness?’” Messonnier said at the time.

The comment sent US stocks into a tailspin and prompted Trump to form a White House coronavirus task force led by Vice-President Mike Pence the next day.

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The task force, which also includes Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, and Deborah Birx, deputy to Vice-President Mike Pence in the group, has run near-daily briefings since it was established.

The CDC “remains the best place in the world, to go for information on coronavirus … and we are less safe when we’re not hearing from the CDC regularly”, Frieden said.

Additional reporting by Owen Churchill.