Enrollment in the state's new health insurance marketplace continued lagging behind even worst-case projections in November - while also proving a particularly tough sell among the coveted "young invincibles" crowd.
Connect for Health Colorado counted 9,980 newly enrolled people in October and November, below the initial projection of 11,108 enrollments that marketplace officials expected to reach by Nov. 13.
The updated tally troubled at least two board members overseeing the marketplace, in part, because it appeared to include a lack of young customers.
As of Nov. 23, 17 percent of Coloradans covered under exchange-based plans were ages 18 to 34, according to the first demographic breakdown offered by Connect for Health Colorado since it opened Oct. 1.
The "young invincibles" customer base is critical to the success of the exchange, because they're generally viewed as healthier than other age groups - thus, leveling the risk pool and possibly lowering future insurance rates, experts say.
Coloradans ages 55 through 64 comprised the largest demographic, with 43 percent of the enrollees from Oct. 1 through Nov. 23.
Most people ages 65 and over are automatically eligible for Medicare, leaving them out of the marketplace's customer pool.
"Those aren't long-term healthy numbers," said Dr. Mike Fallon, a marketplace board member. "Obviously we're looking for as many young people who have not been insured to enter the marketplace.
Colorado lawmakers established Connect for Health Colorado after passage of the Affordable Care Act (or Obamacare) as a way of avoiding Healthcare.gov, the federal government's marketplace serving 36 other states.
Since its launch Oct. 1, the federal marketplace has been riddled with glitches and errors, while the website for Colorado's state-run exchange has been running far more smoothly.
Connect for Health Colorado's long-term viability will rely, in part, on money collected from plans purchased though its website - placing an onus on robust enrollment totals, Fallon said.
But while the number of enrollments offers some insight into the marketplace's success, the overall health of those enrollees also could factor into the affordability of insurance premiums in 2015 and beyond.
Marketplace officials have repeatedly said they expect young people to "wait until the last minute" before enrolling. Coloradans have until Dec. 23 to purchase coverage that goes into effect Jan. 1.
Monday's enrollment update shows young shoppers will continue to be a focus of marketing campaigns, said Jeff Bontrager, Colorado Health Institute's director of research on coverage and access.
Already, marketing campaigns have targeted young adults in Colorado - an age group that's typically proven reluctant to purchase health insurance, often citing cost.
Twenty-seven percent of Coloradans ages 19 to 26 are uninsured, according to the 2013 Colorado Health Access Survey - the state's largest uninsured age group. Nearly 23 percent of Coloradans ages 27 to 34 also went uninsured.
The state's marketplace is in the midst of a $4 million marketing campaign to woo shoppers, featuring many ads that show a skateboarder, proclaiming "If you push yourself, protect yourself."
And a campaign by two unaffiliated nonprofits garnered national attention for ads depicting a woman holding birth control pills and college students doing a keg stand, beside the question "got insurance?"
The campaign, sponsored in part by the Colorado Consumer Health Initiative, released five new "got insurance?" ads Monday, each depicting a parent or two with kids.
An initiative spokesman downplayed concerns Monday that not enough young adults had signed up for coverage.
The figures likely reflect a rush of people who had pre-existing conditions or who badly needed health coverage, said Adam Fox, the nonprofit's director of strategic engagement.
He pointed out that Coloradans have until March 31 to purchase plans through the exchange, as long as they don't mind coverage taking effect later in 2014.
"We're two months into a six-month open enrollment period," Fox said. "There's a lot of time for many more people to get enrolled.
"And really, what we know from Massachusetts, in general, is that a lot of people waited until the last minute. And young adults tend to be more prone to wait until they have to sign up."