The new coronavirus pandemic that has infected more than 16 million people is easily the worst global health emergency the World Health Organization (WHO) has faced, its director general Tedros Adhanom Ghebreyesus said.
Only with strict adherence to health measures, from wearing masks to avoiding crowds, would the world be able to beat it, Dr Tedros added at a virtual news briefing in Geneva.
"Where these measures are followed, cases go down. Where they are not, cases go up," he said, praising Canada, China, Germany and South Korea for controlling outbreaks.
Resurgences of the coronavirus in various regions, including where nations thought they had controlled the disease, are alarming the world, with deaths nearing 650,000.
WHO emergencies programme head Mike Ryan said far more important than definitions of second waves, new peaks and localised clusters, was the need for nations around the world to keep up strict health restrictions such as physical distancing.
"What is clear is pressure on the virus pushes the numbers down. Release that pressure and cases creep back up," he said, acknowledging, however, that it was virtually impossible for nations to keep borders shut for the foreseeable future.
Dr Tedros emphasised the priority remained saving lives.
"We have to suppress transmission but at the same time we have to identify the vulnerable groups and save lives, keeping the death rates if possible to zero, if not to a minimum," he said.
Keeping borders closed not a 'sustainable strategy'
Keeping borders closed to halt the spread of Covid-19 is unsustainable, the World Health Organization said, urging countries to adopt comprehensive strategies based on local knowledge of where the virus is spreading.
Border closures and travel restrictions remain an important part of many countries' strategy to combat the coronavirus.
At the same time, rising cases in a range of countries in Europe and elsewhere that had loosened measures after appearing to get their outbreaks under control have spurred discussions of possible fresh border closures.
But the UN health body warned that such measures cannot be kept up indefinitely, and are also only useful when combined with a wide range of other measures to detect and break chains of transmission.
"Continuing to keep international borders sealed is not necessarily a sustainable strategy for the world's economy, for the world's poor, or for anybody else," Dr Ryan said.
"It is going to be almost impossible for individual countries to keep their borders shut for the foreseeable future," he said, pointing out that "economies have to open up, people have to work, trade has to resume".
He acknowledged that when it comes to Covid-19, it is impossible to have a "global one size fits all policy" because outbreaks are developing differently in different countries.
While countries with rampant community transmission may need to use the blunt instrument of lockdowns to gain control of the situation, others should be burrowing down to get a clear overview of where and how the virus is spreading at a local level.
