As long as the coronavirus that causes Covid-19 is still circulating somewhere in the world, every country and every person remains at risk.

Giving the warning yesterday, Dr Takeshi Kasai, the World Health Organisation's (WHO) regional director for the Western Pacific, said countries looking to ease lockdown measures need to stay vigilant.

Speaking at the virtual World Economic Forum-WHO joint briefing on Covid-19 response in Asia-Pacific, Dr Kasai said he understands that everyone is eager to move on, but the process of easing restrictions should not be rushed.

"Easing restrictions too quickly would bring on a resurgence of diseases," he said. It needs to be done in phases based on scientific evidence and data on the local context in each country."

Dr Kasai also cautioned several times during the hour-long forum: "As long as the virus is circulating in this interconnected world, and until we have safe and effective vaccines available, everyone remains at risk."

What countries and people have to do is "to find a way to live with this virus for now. And this is what we call the new normal". With the exception of Hubei in China, this region has been spared widespread community spread of Covid-19.

But the risk remains and the world body is "encouraging every country to prepare for large-scale community outbreak", he said.

When curbs are eased, the key to controlling the virus is to ensure a well-functioning system to detect and isolate cases, and to trace and quarantine their contacts.

Countries also need to keep a close eye on the use of healthcare, such as intensive care units.

Dr Kasai said the WHO is working with countries "on how to ease measures safely in a way that protects public health, prevents new waves of infections, and allows society to regain some degree of normality".

And individuals have a big role to play in this.

They need to maintain healthy practices that protect not only themselves but also their families, friends, colleagues and their communities. That, he said, is "the foundation of our ability to rebound. We are in this together and can only get out through this together".

The WHO said on Wednesday that the virus could be here to stay.

"It is important to put this on the table: This virus may become just another endemic virus in our communities, and this virus may never go away," the world body's emergencies expert Mike Ryan told an online briefing.

"I think it is important we are realistic and I don't think anyone can predict when this disease will disappear," he added.

But the world has some control over how it copes with the disease, although this would take a "massive effort" even if a vaccine was found - a prospect he described as a "massive moonshot".

At the forum, in reply to a question from a journalist on whether a vaccine, when available, would be distributed equitably, Dr Kasai assured that vaccines belong to everybody around the world.

"This is not something that the country which produces reserves (for its own use). It should be distributed equally," he said.

This will be possible with the pledge of US$8 billion (S$11 billion) by more than 50 countries earlier this month for the fight against the Covid-19 pandemic.

Ms Tan Hooi Ling, co-founder of ride-hailing and food-delivery company Grab, and one of four speakers at the forum, said her company is looking at the logistics of delivery and "how to get vaccines to everybody".

She said: "What's really important is to partner with governments to figure out who should have those vaccines. For that, data is key."