Officials said that figures show nearly half of those who just signed up for insurance currently do not have coverage through the federal insurance marketplace. (Don Ryan/AP)

Nearly a half-million people chose health plans through HealthCare.gov during the first week of the new open-enrollment period in the online insurance marketplace, federal health officials announced Wednesday.

The figures show that nearly half of those who have just signed up for insurance do not currently have coverage through the federal insurance marketplace. That group — 48 percent of the 462,000 people who picked a health plan during the week that started Nov. 15 — is significant, because a major goal during the enrollment window this time is attracting uninsured Americans who did not get coverage through HealthCare.gov in its maiden year.

On the other hand, the figures indicate that few of the 6.7 million people who already have insurance through the marketplace moved immediately to renew it.

The report also shows that the interest in — or ability to get — insurance is running ahead of what was seen during the first HealthCare.gov enrollment period, which began in October 2013 and was marred in its initial months by computer problems that prevented many from signing up.

In the first month of last year’s enrollment period, slightly over 500,000 people completed insurance applications through the federal marketplace, and nearly 30,000 went on to choose a health plan. The new figures show that this year, in the first week, just over 1 million people completed applications and almost half of them picked a health plan.

“We are off to a solid start,” Health and Human Services Secretary Sylvia Mathews Burwell said.

Still, she and other senior federal health officials maintained the cautious tone they have used for months in setting public expectations for the second opportunity to sign up for coverage through the marketplaces.

“We are only 10 days in,” said Andy Slavitt, principal deputy administrator of the Centers for Medicare and Medicaid Services, the branch of HHS that oversees HealthCare.gov. “We still have a lot of work to do every day.”

In providing a snapshot of the first week’s activity on HealthCare.gov, HHS officials departed from their practice last year, when they said they were unable to release enrollment data more frequently than monthly.

The figures released Wednesday are from about three dozen states relying on HealthCare.gov, which was created as a major part of the 2010 Affordable Care Act. The new data does not include the separate health exchanges in place in 13 states, including Maryland, and the District. Nor does it contain any breakdowns among the states in the federal exchange — or, among people renewing coverage, how many are keeping their current health plans and how many are switching to a different plan.

People who choose a health plan must begin paying premiums before they become insured.

In a conference call with reporters, Burwell said the new figures reflect only enrollment in health plans that provide medical coverage. Last week, HHS was embarrassed by revelations that it had inflated enrollment tallies for coverage in 2014 by adding in a few million people who had coverage solely for dental care — an accident, HHS officials have said.

“These numbers have been checked and do not include dental,” Burwell said Wednesday, adding that staff members are continuing to examine how the erroneous figures were provided to the public.

The snapshot also indicates that federal call centers, with staffers trained to answer questions for people considering insurance through the market­places, have so far been able to keep up with consumers; the average wait to speak with a staff member was just over three minutes.

At a time when federal officials are eager for more Latinos to become insured, the volume of calls from people requesting a Spanish-speaking representative has been relatively light; so has the number of people browsing health plans on a Spanish-language section of the federal insurance Web site.

Slavitt said that since HealthCare.gov opened this month, there have not been any times when the site was unavailable because of computer problems — a common occurrence last year. So far, he said, the Web site’s busiest period consisted of about 55,000 people using it simultaneously — far below the 250,000 it is supposed to be able to accommodate. Still, there have been two occasions so far, he said, when insurance-seekers on certain parts of the site were steered into an online waiting room for brief periods.

He predicted that the Web site will be able to handle big upswings in traffic that, based on last year’s experiences, are likely to occur as two deadlines approach: Dec. 15 is the last day for people to renew coverage for 2015, and Feb. 15 is the end of the three-month enrollment window — half as long as last year’s.

Earlier this year, the Obama administration decided that, after Dec. 15, it would automatically renew the coverage of anyone who bought insurance on HealthCare.gov for this year and had not taken steps by then to continue or change their health plan for 2015. Still, health officials recently have been urging those who already have coverage to return to the Web site to update information about their income and any changes that would affect their insurance or its price — and to compare their current coverage with other health plans available to them.

During the first week, fewer than 250,000 did so.