Former CEO of Microsoft Bill Gates says only a complete lockdown of the US will contain the spread of coronavirus.
The billionaire has warned that shutting down states individually won't work, and the only way to tackle Covid-19 is a "serious" shutdown, similar to China.
He suggested a nationwide lockdown between six to ten weeks would be necessary.
Gates, whose Bill and Melinda Gates Foundation has pledged $100 million to fighting coronavirus, told CNN : "China did their shutdown and they did it in a very serious way.
"After a six-week period of a shutdown that's more extreme than some states in the United States are likely to do, they were able to start opening up again, and the total number of cases there is very, very small.
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"That's very good news."
States in the US vary in terms of how they are dealing with coronavirus, with Gates also calling for the level of testing to be raised.
"We're entering a tough period where if we do it right, we'll only have to do it once for six-ten weeks," he said.
"But it has to be the whole country. We have to raise the level of testing and the prioritisation of that testing quite dramatically in order to make sure we go through one shut down so that we take the medical problem and really stop it before there's a large number of deaths."
New York has more coroanvirus cases than any other US state, with almost 60,000 confirmed, and despite some others such as South Dakota reporting just 90 cases, Gates said a national shutdown is still essential.
"Let's say you have 100 cases and let's say you don't do a shutdown - then it grows 33 per cent per day," he added.
"The sooner you engage in the shutdown, the easier it is to get to that peak.
"Basically the whole country needs to do what a part of China has done where they had these infections."
US President Donald Trump warned coronavirus deaths in the country are expected to peak in two weeks as advisors warn the outbreak could kill 200,000 citizens.
Social distancing in the country has been extended until April 30 after Trump admitted hopes that the economy would be running again by Easter were "aspirational".