WASHINGTON • Under the Affordable Care Act, also known as Obamacare, an estimated 20 million Americans have gained health insurance, but the future of this landmark healthcare law is uncertain. President-elect Donald Trump and his administration have promised to repeal and replace it.

The programme found its feet after a problematic roll-out in October 2013. Technical problems on the website left many Americans frustrated and unable to sign up for their insurance plans. Republicans leapt at the chance to cast the law as unworkable and an example of the failure of big government.

Nevertheless, 7.1 million people had signed up for Obamacare by April 2014. Until then, many experts had deemed the United States the last major developed country without universal health coverage.

President Barack Obama said in a White House speech in the months after the roll-out that the aim to narrow the gap between those with health coverage and those without had begun.

"That's what the (law) is all about; making sure all of us and all our fellow citizens can count on the security of healthcare when we get sick," he said.

A Gallup survey in September last year found that 51 per cent of Americans disapprove of the law, while 44 per cent approve of it. But last month, another poll showed that only 25 per cent of Americans want the law to be entirely repealed.

The Obama administration's Council on Economic Advisers also issued a report card on the law last month. One of its top findings showed that the uninsured rate has declined in all income groups since the law came into full effect in 2013.

Mr Trump has backed down on his campaign rhetoric to repeal the law on his first day in office, now saying that he would keep key provisions. These include guaranteed coverage for pre-existing conditions and allowing children to stay on their parents' plans till the age of 26, but he has yet to release details on what his alternative plan might look like.

Melissa Sim