The Affordable Care Act health insurance marketplaces just hit a record: 16.3 million people signed up for the insurance also known as Obamacare.

That is a million more people than signed up for ACA health insurance last year. (Enrollment is closed on Healthcare.gov, but still open on state marketplaces in California, Washington, D.C., New Jersey, New York and Rhode Island until January 31.)

"Enrollment at Healthcare.gov is up a whopping 50% since President Biden took office," Ambassador Susan Rice, domestic policy advisor to the president, told reporters on Wednesday. Among the enrollees were 3.6 million people who were new to the marketplace, she added, people who "will now have the peace of mind that health insurance brings."

What's driving the upward trend? The big reason is that the plans are cheaper for people than they used to be. The federal government has pumped billions of dollars in recent years into subsidies to keep costs down for consumers.

Health officials say 4 out of 5 enrollees qualify for plans that cost $10 or less per month. And 5 million people who are uninsured qualify for zero dollar premium plans, according to a recent analysis from the Kaiser Family Foundation.

Another reason why more people are signing up is likely because there's more logistical help. The Affordable Care Act created a program of "navigators" – people across the country who are trained to help consumers understand their options and get signed up for a health plan. It's a service paid through government grants.

The Trump administration slashed the funding for this program. The Biden administration shored it up. Katie Roders Turner is executive director of the Family Healthcare Foundation. Her organization is part of the Tampa Bay Navigator Project in Florida, which went from having a team of 16 navigators to 35 this year – more than double the staff.

"This year we really caught our stride," Roders Turner says. "We've been really able to spread out the need and the demand amongst those navigators."

Happy tears in central Florida

One of the people her organization helped in recent weeks was Erin Dimmig. She and her husband, Tyler, are 30 years old and they live in Plant City, Florida. Right now, she describes herself as "very pregnant" – she's due with her first child in February.

This fall, "my husband got a new job offer and that puts him in a 90-day insurance gap, and we were due in 60 days," she explains. They couldn't afford to keep paying for the insurance they'd had through his old job – COBRA was going to cost them $1,600 a month.

She says she had no idea where to start to look for alternatives. She googled her way to Healthcare.gov, the federal marketplace, which Florida and 32 other states use. (State-based sites can also be accessed through Healthcare.gov).

She started to answer questions like size of household, income, and other details. "Once you click the 'you're pregnant' button, there's all sorts of confusing questions, and I was absolutely in over my head," she says.

She clicked over to the directory to find navigators in her area, and found a local community center on the list. Soon the Dimmigs went to see navigator Jorge Masson.

"We walked through the whole process with Jorge. He helped us pick a plan that worked for us. It actually ended up working out better to split our insurance," she says. "It will end up saving us about $9,000 with childbirth and all of that. I cried when we found out that we were going to be saving a lot of money."

Switching gears to handle Medicaid enrollment

Biden administration health officials don't have much time to celebrate the success of open enrollment because a huge challenge looms: How to prevent millions of people from becoming uninsured as pandemic Medicaid rules sunset?

After the COVID-19 public health emergency declaration in 2020, states weren't allowed to require people to fill out forms confirming they were still eligible. As a result, new people enrolled, but no one disenrolled, and the program swelled. About 90.9 million people now have Medicaid or CHIP, the Children's Health Insurance Program.

Starting in April, states will be able to begin "redeterminations" again. More than 15 million people could lose Medicaid during that process, according to an estimate from the Department of Health and Human Services released this summer. The analysis suggests nearly half of those losing coverage will do so because of administrative issues – such as challenges with filling out the paperwork to reapply – and not because they no longer qualify for coverage.

The agency responsible for both Medicaid and the insurance marketplaces – the Center for Medicare and Medicaid Services – is working feverishly to help smooth this transition and limit the number of people who become uninsured.

As open enrollment comes to a close, some navigators who had been brought on to help will be going back to other roles with their community organizations, but federal health officials say they hope that support system will stay in place to be able to help people who find themselves disenrolled from Medicaid in the spring.

"Last year, we included additional navigator funding – to the tune of $12 million – to be exercised when unwinding happened," Ellen Montz, Deputy Administrator and Director of the Center for Consumer Information and Insurance Oversight at CMS, explained to reporters on Wednesday. That funding "came at a time that will allow navigator organizations to keep on their staff from open enrollment and move into the unwinding process."

Roders Turner in central Florida says her navigators are standing by to help people as the unwinding begins on April 1.

"We've got an amazing group of people who are prepared to be the workforce to help with the Medicaid unwinding – identify options for people that are coming off of Medicaid, or help them fill out the applications that are needed to maintain their coverage," she says. "We're definitely prepared – and we know that we're going to be needed – as Medicaid unwinding takes place."

Note: This story originally aired and was published on Jan. 13. It was updated Jan. 25.