SINGAPORE - It could take several years for the coronavirus to go around the world and run its course unless something happens to abort that process, says Prime Minister Lee Hsien Loong, adding that the world will have to brace itself for a long battle ahead.

In an interview on Sunday (March 29) with CNN's Fareed Zakaria about Singapore's much-lauded response to the Covid-19 pandemic, Mr Lee said he hesitates to call the Republic a "success story".

In response to the suggestion that Singapore has contained the virus outbreak, he said: "I hesitate to talk about success because we are right in the midst of a battle, which is intensifying."

He does not see the pandemic going away in a couple of months and expects it to spread to other parts of the world such as India, Africa, South-east Asia and Latin America.

"By the time it goes around the world, and then finally runs its course, I think that is several years, unless something happens to abort that process."

Mr Fareed also asked about the role of the United States in the pandemic, noting that President Donald Trump did not seem interested in taking the lead.

To this, Mr Lee said the world has greatly benefited from American leadership in such crises for decades. "If America is in a different mode, well, we will get by and I think other configurations will eventually work out, but it would be a loss."

America, he added, has the resources, the science, the influence, the soft power, and the track record of dealing with these problems convincingly and successfully. "It is a pity not to put those resources to work now, to deal with this very grave challenge to mankind."

He also called upon the US and China - which have been pointing fingers at each other for the outbreak - to work together to combat the pandemic.

"It is a most unfortunate situation to be in. I mean, US-China relations have been complicated even before this. But if we are going to deal with this virus, you have got to get all the countries to be working together, in particular, the US and China.

"Under the best of circumstances, it is going to be a very difficult challenge for mankind. But if the US and the Chinese are swopping insults and blaming one another for inventing the virus and letting it loose on the world, I do not think that that is going to help us solve the problem sooner."

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China, where the virus originated, had been criticised for not being sufficiently transparent about the crisis during its early days. Asked whether that had - as some critics charged - exacerbated the situation, Mr Lee said: "I am sure that there were many aspects of the Chinese response to this outbreak which they will look back upon and believe that they should have done better.

"But I do not think overall that one can say this would not have happened if only the Chinese had done the right thing. Because you look at the way the outbreak has continued to grow and spread in many countries, and they do not have the Chinese government and yet they have not found it easy to keep the outbreak under control in their country.

"I think that we are in a very difficult situation and it is most constructive for us now to look ahead and find the best way to move forward and deal with a problem which we now have."

He said that Singapore took Covid-19 very seriously from the beginning. "We watched what was happening in Wuhan, in China. We prepared our people. In fact, we have been preparing for this since Sars, which was 17 years ago."

To tackle the virus through herd immunity, a controversial strategy to allow a community be infected and build immunity to the virus, would be very painful, he said, as a large proportion of the population would have to be infected.

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The other way is to flatten the curve, and that will take a long time. "You have got to hope for an off ramp to get off that path, and the only visible way to get an off ramp is to have either a treatment or an effective vaccine.

"That is some distance down the road, but many very smart people are working very hard at it. I can only hope and pray that they will make some progress soon."

Asked if Singapore had been able to contain the virus because of its "paternalistic system", Mr Lee said that the Government had not exercised "extraordinary powers".

Instead, he said, in the battle against the virus, trust and transparency are key. "We put a lot of effort into explaining to (the public) what is happening, speaking to them and I have done it a few times directly on television, so people know that we are level and we tell it straight.

"We are transparent - if there is bad news, we tell you. If there are things which need to be done, we also tell you. I think that you have to maintain that trust because if people do not trust you, even if you have the right measures, it is going to be very hard to get it implemented."

He added that the Singapore Government has not been using phone data to do contact tracing, but rather "traditional detective work".

"We have been interviewing people, asking them, interviewing them, tracking down their contacts, interviewing their contacts, trying to piece a story together... We hope to get a quick answer out within a couple of hours, but in fact we have pursued the cases for days to try and pin down, who talked to whom and who might have given the virus to whom."

He described how Covid-19 has crippled the aviation and tourism industry, disrupted supply chains and upended the gig economy.

It will take quite a while for jobs - which depend on normal socialising - to return.

"I do not see that coming back until such time as people gain confidence that they have a hold on the virus, that we can resume normal socialising, normal travelling, normal human intercourse. I think that is quite some time down the road."

Asked if the pandemic might lead him to postpone his decision to step down as Prime Minister, Mr Lee demurred: "I think this crisis keeps my hands full. Let us just focus on that for now."