Bright orange ads plaster Chicago trains and buses. An endless loop of television commercials sandwiches the alley-oops and upsets of March Madness. Promotions run during Chicago Bulls games, on hip-hop radio stations and on web sites like BuzzFeed, Pandora, The Onion, Facebook, Twitter and YouTube.

The message and the medium leave no doubt about whom the state of Illinois, federal government, advocacy groups and insurance companies are looking to reach in the final days of open enrollment in new health insurance plans under the Affordable Care Act.

The question is whether the last-minute frenzy will drive enough of them to sign up by 11 p.m. Monday, the deadline to enroll in Obamacare.

Although the Obama administration said Wednesday that people who started to apply for coverage but were unable to finish by Monday will have additional time to complete the process, officials are pushing people to enroll now.

After a disastrous start to the six-month enrollment period for health coverage under President Barack Obama’s signature health law, the campaign to generate interest among the young and healthy is at a crucial stage.

And groups with a stake in the law’s success are chasing these so-called young invincibles, the hard-to-reach consumers seen as key to balancing the pool of sicker, older people who may need more care.

“We certainly have increased messages that resonate with a younger consumer, and that seems to be working,” said Kurt Kossen, vice president of retail marketing for Health Care Service Corp., the parent company of Blue Cross and Blue Shield of Illinois. “We’re starting to see more younger consumers starting to purchase plans, and we hope to see more of that in the coming week.”

The state’s largest insurer has held events this month at community centers, universities and other venues, seeking to reach as many young people as possible.

Through February, slightly more than 113,000 people in Illinois have signed up for new health plans, a figure on target with federal projections but far off the pace needed to meet the state’s internal goal of enrolling 300,000 in 2014.

Of those who picked a plan, about one-fourth are ages 18 to 34, a percentage the state and insurers are hoping to raise substantially this month.

Get Covered America, a national enrollment outfit with close ties to the White House, has held events throughout Illinois every day this month, with volunteers making thousands of phone calls to the uninsured, going door to door in Chicago neighborhoods and showing up at job fairs, stores and churches to encourage people to sign up.

Illinois’ enrollment organization, Get Covered Illinois, dispatched an orange-and-white-branded RV around the state, making stops at a Chicago Fire soccer match, the downtown St. Patrick’s Day parade, libraries, malls, colleges and community centers. It is also responsible for a major push into new media, often using humor to target young people.

“We’re pulling out all the stops to get the message out that this is it. March 31 is the deadline, and if they don’t enroll by March 31, they won’t get another opportunity until November,” said Jennifer Koehler, Get Covered Illinois’ executive director. “We’re really focusing on our 18- to 34-year-old demographic, who we think are going to be some of our toughest holdouts.”

Federal and state officials and insurance executives say the effort is beginning to show results.

Last weekend, the getcoveredillinois.gov web site logged more than 75,000 unique visitors, a record for any three-day period thus far, Koehler said. On Monday, the state call center fielded more than 7,600 customer inquiries, also a daily record.

On Tuesday, more than 1.2 million people visited the federal enrollment web site, HealthCare.gov. More than 500,000 others phoned the federal call center from Monday through Tuesday, the federal officials said.

On Wednesday, the site had more than 1.5 million visits. Overall, the White House said Thursday, more than 6 million people have signed up for health insurance.

To prepare for an expected crush of last-minute customer questions, Illinois will extend hours in its call center from 7 a.m. to midnight from Friday through Monday.

Federal officials say their enrollment web site can support 100,000 concurrent users, and it has about 14,000 customer service representatives who will be on hand through Monday to handle expected high call volume.

Blue Cross and Blue Shield said its web site has logged a 50 percent spike in traffic during the past two weeks, and calls to its sales team are up significantly, Kossen said.

It’s preparing for an even bigger spike this weekend, he said. “We’ve clearly anticipated this would be a very busy week, and we’re staffed up accordingly.”

Aetna, which is offering plans on the Illinois exchange under its own brand and under the Coventry banner, expects a bigger surge this month than it experienced in December, when a wave of consumers signed up for plans effective Jan. 1.

“We’re starting to see a lot more activity,” said Bill Berenson, president of the insurer’s Great Lakes market. “Clearly, as you get closer to the deadline, you’ll have more activity. It’s the nature of the human being.”

Marketing efforts began slowly, in large part because of the troubled launch of HealthCare.gov, which hosts the online insurance marketplaces for Illinois and 35 other states.

A technological meltdown that rendered the web site inoperable for many consumers for most of October and November hobbled the initial sign-up effort and forced Illinois and insurers to hold back major parts of their outreach and ad budgets.

The widely publicized problems online also sowed confusion among consumers, deterring them from seeking coverage options, said Bill Green of the United Way of Metropolitan Chicago, who manages a $1.3 million federal grant and a group of about 60 enrollment counselors throughout the metro area.

“Even into January, there was this idea that every single part of applying was messed up in some way,” Green said. “Enrollment is obviously much lower than we’d like to see. It was kind of a heartbreaker ... and a major hurdle we’ve had to overcome.”

Other outreach groups also pointed to the lack of early marketing and education efforts, particularly outreach to Spanish speakers and young black men.

“That’s the feedback we’ve heard pretty consistently,” said Dominique Williams, a program director for the nonprofit LISC Chicago, who oversees nearly two dozen navigators and in-person counselors throughout Chicago’s South and Southwest sides.

Williams, whose team has helped enroll nearly 1,700 people in new coverage, said those numbers might have been higher if the state and federal government used targeted messaging better.

Insurers also had to adjust marketing plans on the fly to adapt to a series of midcourse policy changes from the Obama administration, including a decision made late last year to allow them to offer old insurance policies once slated for cancellation, even if they didn’t comply with the law’s tougher regulations.

The change set off an administrative nightmare among insurers that was particularly painful for Blue Cross, which controls the vast majority of the individual market in Illinois.

Its customers found themselves stuck in limbo, reporting problems like double billing on policies, long delays for enrollment confirmation and four-hour waits to talk to customer service agents. Consumers continued to gripe about unsolved issues well into this month, flooding the insurer’s social media pages on Facebook and Twitter with their grievances.

Instead of focusing its efforts solely on promoting new policies and helping new customers shift into coverage, Blue Cross had to pivot, dedicating resources to clean up the mess.

In response, the insurer hired more than 600 new call center workers, permanently extended call center hours and set up a new billing and payment hotline, Kossen said.

“We’re doing literally everything we can,” he said. “Is our customer service to the level we’re used to providing to consumers? No. But is it significantly improved from January? Yes. We’re not where we want to be, and fixing that is a top priority.”

The government and insurers also are reinforcing the message that, with some exceptions, people who do not enroll in insurance by the Monday deadline will face a tax penalty next year of up to 1 percent of their annual household income, or $95 per person, whichever is higher.

Some people will be able to sign up beyond the deadline if they experience a major life change, like getting married, losing a job or having a baby.

Although the Obama administration this week softened the March 31 deadline with a decision to allow people who have started applications on HealthCare.gov a grace period to complete their enrollment, state and federal officials continue to press consumers to enroll as soon as possible to avoid problems.

In a video uploaded to YouTube on Tuesday by Get Covered Illinois, Obama makes one final plea: “Don’t just think about it, just do it. It’s last call for 2014, so get covered today.”

©2014 Chicago Tribune