WASHINGTON — With the next open-enrollment period for health insurance under the Affordable Care Act six weeks away, the National Association of Chain Drug Stores has advocated administrative changes to help people seeking health coverage in 2015.

Exchange call centers should remain open on Christmas and New Year’s Day, beneficiary eligibility files should be updated nightly, and pharmacists should be allowed one-time overrides in January, NACDS president and chief executive officer Steve Anderson wrote to Marilyn Tavenner, administrator of the Centers for Medicare & Medicaid Services (CMS).

The next enrollment period for ACA plans runs from November 15 through February 15. The Congressional Budget Office projects that 13 million people will get insurance through online exchanges, 5 million more than during last year’s bungled rollout of HealthCare.gov.

Anderson said there were concerns last year that some state run call centers were not open on holidays. New Year’s Day service is especially important for addressing confusion and transitional problems, he said.

Also, patients may visit a pharmacy in January, shortly after enrolling in a plan, only to find that their coverage is not yet active, he said. The likelihood of that happening will increase if plans fail to update patient eligibility files every night. Nightly updates will “provide for a smooth transition from coverage to care,” Anderson wrote.

“Finally, at the start of a plan year, there often can be confusion concerning coverage for specific medications for new plan enrollees,” he said. “Difficulties in adjudicating such drug claims can lead to continuity of care problems as patients are delayed or denied access to the medications they need.”

To avoid repercussions, Anderson asked for overrides of prescription drug claim denials in January 2015.

“CMS should further make clear that the plans have the responsibility for paying for the overridden claim once the claim is approved,” he said. “This will provide patients with access to the drugs that they need while they work through coverage issues with their insurer, or work with their prescriber to find a substitute covered ­medication.”

Plans bought under the ACA are covering 7.3 million people, the Obama administration reported in September. While the president had said in April that 8 million people had enrolled, Tavenner told a House committee some of those may have gotten insurance through work or discovered they were eligible for Medicaid. Others may have not paid their premiums, she said.

Larry Merlo, president and CEO of CVS Health, said the ACA has provided “a modest benefit” for the company. The company is gaining more from Medicaid expansion under the law than from exchange enrollment, he said during a speech here at the National Press Club.

Estimates of how many enrollees are newly insured “are all over the board,” he said, citing a range from 25% to 80%.

“I’m not sure we know the numbers in terms of what percent are really new to insurance,” Merlo said. “That’s not the same in Medicaid.”

While the last open-enrollment period ended on March 31, some people have signed up for plans since then, capitalizing on extensions for those who married, divorced, had a baby or were thwarted by HealthCare.gov’s technical problems.

Just this month congressional investigators reported that the website risked a breach of personal information. While the administration has taken steps to safeguard HealthCare.gov’s privacy, “significant weaknesses remain that put these systems and the sensitive, personal information they contain at risk of compromise,” said Gregory Wilshusen, director of information security for the Government Accountability Office (GAO).

More than 20 security issues must be resolved, the GAO found.

“There’s very little that concerns me more on a daily basis than the security of this website,” Tavenner testified. “I will always worry about the safety and security of the website.” To date there has been no breach of personal information, she said.