Countries across the world must take a comprehensive approach to fighting the coronavirus pandemic and isolate, test and trace as many cases as possible, the World Health Organization (WHO) said on Wednesday.

"To suppress and control the epidemic, countries must isolate, test, treat and trace," the WHO's Director General Tedros Adhanom Ghebreyesus told a media briefing.

"If they don't, transmission chains can continue at a low level and then resurface once physical distancing measures are lifted," he added.

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He said the test and trace strategy "must be the backbone of the response in every country", adding the coronavirus was "an unprecedented opportunity to come together as one against a common enemy: an enemy against humanity".

Tedros also said to speed the search for potential therapies and drugs for the COVID-19 infection, the WHO and its partners are organising a multi-country study to analyse and compare some as-yet-untested treatments.

"This large international study is designed to generate the robust data we need to show which treatments are the most effective," Tedros said. "We have called this study the solidarity trial."

Market scramble

WHO officials also called for "order and discipline" in the market for health equipment needed to fight the coronavirus pandemic, and said WHO was in discussions with China and others to ramp up supplies.

"There is a scramble on the market, and we need order and discipline on that," Mike Ryan, head of WHO's emergencies programme, told a virtual press briefing.

"Countries like China and others have immense capacities for ramping up production and we are working with them to see how that can be achieved, and other large scale producers of such equipment," he added, referring to supplies such as ventilators.

More than 200,000 cases of coronavirus have been reported worldwide, although death rates have varied across countries and have been particularly high in Italy, where 475 new deaths over 24 hours were reported on Wednesday.

Ryan said the difference was likely caused by the "astonishing" number of cases within the clinical system as well as the high number of elderly people in Italy.

"When patient numbers begin to overwhelm, it becomes a simple factor of your ability to provide adequate care," he said, praising the courage and bravery of the healthcare workers treating more than 1,200 patients in intensive care.

"It's an astonishing number. The fact they are saving so many is a miracle in itself," he said.