Meet Sylvia Burwell -- President Obama's pick for the next Health and Human Services secretary. Here is everything you need about her career in less than a minute. (Jackie Kucinich, Theresa Poulson and Jeff Simon/The Washington Post)

If Sylvia Mathews Burwell is confirmed as the next secretary of Health and Human Services, it puts her in charge of a sprawling health-care overhaul that's still gaining its footing and is under constant attack from opponents. The Obama administration is celebrating the more than 7.5 million people who have signed up for coverage in Obamacare health insurance marketplaces, but there are big implementation challenges for the next HHS leader.

Here are the major challenges the next HHS chief will face:

1. Obamacare politics aren't changing

Resigning HHS Secretary Kathleen Sebelius may have taken the brunt of criticism from Obamacare opponents, but their objections to the law won't change with her departure. The midterm elections are just seven months away, and the Republican campaign playbook features a heavy dose of Obamacare opposition.

As much as possible, the Obama administration wants to dodge potential negative headlines over the health-care law leading up to November. Opponents, like Americans for Prosperity, have already dumped millions of dollars toward anti-Obamacare ads in states with vulnerable Senate Democrats facing reelection, and they have more cash to spend.

Remember the wave of bad publicity over cancelled health plans last year? There could be a second round this year, when small businesses face the end of their health plan years. Many small businesses opted for early renewal last year, but their old health plans could face cancellation in states that aren't allowing non-compliant plans to continue.

Health-care costs and access to providers are two major issues to watch over the next few months. Not much is yet known about how people are using their new Obamacare coverage or whether they believe it's a good value, but HHS has shown a willingness to take quick administrative action when implementation problems arise.

2. Tech problems are far from over

The consumer-facing side of has been working pretty well since early December, but the job is far from over. The administration is still building the back-end payment system for insurers, many Medicaid applications coming through are still caught in limbo, and the enrollment portal for the small business exchanges remains unfinished.

On top of that, a handful of states are dealing with enrollment Web sites still in pretty rough shape. Maryland already ditched its enrollment system for one like Connecticut's, Oregon may drop its system to join, and Massachusetts is hoping for a "functional" Web site that meets the law's basic requirements by November. A few others are also struggling.

The one thing working in the new HHS secretary's favor: There's actually a point person on the technology side, something the administration lacked when launched Oct. 1. Former Microsoft executive Kurt DelBene has been overseeing the tech operations for a few months now.

3. Planning for 2015 enrollment

Enrollment in 2014 health plans is winding down, with April 15 as the last day for people who experienced sign-up troubles to pick a health plan. But it's time to start thinking about enrollment in 2015 plans, which is scheduled to start Nov. 15.

HHS and its new secretary will have just a short window to plan for next year and assess what worked in the 2014 enrollment period and what didn't. The 2015 enrollment period is supposed to be considerably shorter — just three months instead of six months.

Though the administration hasn't set a target for 2015, the Congressional Budget Office already laid down the marker, projecting that the total number of enrollees through Obamacare insurance marketplaces will hit 13 million by the end of 2015. They're already more than halfway there: 7.5 million have signed up through the exchanges in 2014, and that number may grow before the next enrollment period starting Nov. 15.

4. The unfinished Medicaid expansion

Twenty-four states haven't joined the health-care law's expansion of Medicaid, leaving about 5 million people stuck in a coverage gap. In many of these states, there's not much the administration can do except hope for favorable elections.

One of Sebelius's greatest achievements was working with Republican governors in states like Arizona, Iowa and Michigan to expand Medicaid against stiff opposition back home. Still, there's opportunity for the next secretary to bring more states on board. At least three Republican governors in Pennsylvania, Tennessee and Utah are currently discussing Medicaid expansion designs with HHS, and Republican governors from Indiana and Oklahoma are operating on one-year waivers as HHS encourages them to join the Medicaid expansion next year.

5. Keeping insurers, allies happy — and keeping premiums down

The administration needs insurers to make Obamacare work, and insurers need Obamacare to work, which has made for a sometimes-awkward dynamic of cooperation between the two sides during the rocky Obamacare rollout. The administration has already made some concessions to the insurance industry since the failed launch, giving it a break on costs they incurred as a direct result.

One of the key metrics for judging Obamacare's success in its first year will be just how much do premiums rise in 2015. HHS is under pressure to keep premium increases down, but the department is also getting competing pressure from supporters to ensure that enrollees have robust coverage and provider options. HHS already signaled it would provide more stringent health plan oversight and require broader provider networks in 2015. But how will insurers react to this? HHS also provided insurers with more leeway in 2014 and 2015 to design benefit packages, but Obamacare advocates have pushed for a more prescriptive approach from the federal government in the following years.