"Normal" life around the world before the coronavirus pandemic struck may never return, the top US scientist tackling the outbreak said.

Dr Anthony Fauci said at a White House press briefing that gradually countries will again "function as a society but … if you want to get to pre-coronavirus, that might not ever happen in the sense that the threat is there".

"If 'back to normal' means acting like there never was a coronavirus problem, I don't think that's going to happen until we do have a situation where you can completely protect the population … Ultimately, the showstopper will obviously be a vaccine," he said.

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The US has entered what one official called the "peak death week" of the coronavirus, while a watchdog report said hospitals were struggling to maintain and expand capacity to care for infected patients.

A University of Washington model, one of several cited by US and some state officials, now projects US deaths at 81,766 by August 4, down about 12,000 from a projection over the weekend.

Fauci said several therapies were being worked on and potential vaccines were showing promise so hopefully "we will never have to get back to where we are right now".

He added he hopes scientists will develop therapeutic drugs to contain the contagion in the meantime.

The coronavirus has killed more than 74,000 people around the world. The worst outbreak is in the United States where there are more than 362,000 cases and at least 10,781 deaths.

Help on the way?

With the antimalarial approach dominating headlines, doctors are still hopeful one or more of the other therapies being tested will begin to show success.

University of California Los Angeles (UCLA) and Northwell Health are among more than three dozen medical centres participating in clinical trials of Gilead Sciences' experimental antiviral remdesivir, which was previously tested as a treatment for Ebola, but failed to show effectiveness.

Initial data from a separate trial of the drug in China could be announced this month.

"We feel like the hierarchy in terms of the evidence to support its use starts with remdesivir, then to hydroxychloroquine, and then it sort of rapidly deteriorates after that," said Dr Arun Sanyal, a

professor at Virginia Commonwealth University School of Medicine.

Some are keen to see whether blood plasma from recovered coronavirus patients will spur immunity in others - a method used more than 100 years ago. Some experts say that approach has a good chance of succeeding.

Others have focused on the potential of more advanced biologic medicines to quell the processes that put the body's immune system into overdrive in severe COVID-19 cases.

White House officials have predicted between 100,000 to as many as 240,000 people in the US will die from COVID-19, with numbers of deaths peaking over the next several weeks.

"Dr Fauci and I both strongly believe that if we work as hard as we can over the next few weeks that we will see potential to go under the numbers that were predicted by the models," said Dr Deborah Birx, who sits on the coronavirus task force with Fauci.

Fauci said he doesn't accept the death projections. "I think we can really bring that down no matter what a model says."