The Affordable Care Act's fifth enrollment season had a brisk start, as seen in government numbers released Thursday. (HealthCare.gov)

More than 600,000 Americans signed up for insurance coverage under the Affordable Care Act during the first four days of the new enrollment season, according to federal figures that signal a brisk start despite Republicans’ efforts to dismantle the law.

Some 601,462 Americans chose a health plan from Nov. 1-4 in states relying on the federal exchange, the figures released Thursday by the Centers for Medicare and Medicaid Services show.

While CMS officials did not provide a direct comparison with any of the four previous enrollment periods, administration officials said that more than 200,000 consumers selected plans on the first day, more than double the number last year. The officials spoke about the first-day figure on the condition of anonymity because they were not authorized to disclose it.

The overall total for the initial four days compares with just over 1 million Americans who signed up on the federal exchange during the first 12 days of open enrollment in 2016.

But the initial federal figures suggest that the proportion of newcomers to the ACA marketplaces continues to decline. The 22 percent of new enrollees — 137,222 people — during the opening days in November compares with 24 percent in the early days of 2016.

The CMS data reflects only sign-ups in the roughly three dozen states that rely on HealthCare.gov, the federal enrollment website. But the apparent uptick there has been mirrored in states that run their own ACA marketplaces. The vast majority of those exchanges — including California, Colorado, Connecticut, the District, Idaho, Maryland, New York, Rhode Island and Washington — all report an increase in both enrollment and inquiries at their call centers.

Taken together, the early figures show that efforts by President Trump and congressional Republicans to undo much of the 2010 law have not dampened consumers’ willingness to turn to the insurance marketplaces it created. Another factor in the faster pace could be that the enrollment season lasts until only mid-December — half as long as in the past three years.

Unlike during those years, when President Barack Obama urged Americans to buy coverage and the federal government heavily subsidized both advertising and in-person assistance for consumers, federal officials have done little to promote this ACA enrollment period. The Health and Human Services Department slashed the federal advertising budget by 90 percent, cut funding to those assisting consumers with finding plans and shifted the government's messaging.

But another telling, if imperfect, way of gauging the marketplace’s popularity — the average number of consumers who enroll daily — also suggests that this year may be running ahead. An average of about 150,000 signed up on each of the first four days this month, compared with an average of 84,000 during the first dozen days of the past enrollment period.

ACA supporters said they cannot point to a single reason for why more people are renewing coverage early or signing up for the first time.

“Consumers are, generally speaking, expressing urgency with getting this task taken care of and off their to-do-list,” Jennifer Simmons, navigation program coordinator for the North Carolina Navigator Consortium, said in an email. “We are happy to report heavy traffic across the state.”

But other state officials and health-care advocates have expressed concern about whether enrollment will dwindle among rural consumers, many of whom no longer have as ready an access to in-person assistance.

Jessie Menkens, who helps oversee statewide enrollment efforts as the Alaska Primary Care Association’s navigator program coordinator, said in an email that while assisters have seen “steady interest in the Anchorage area,” enrollment in the state’s vast rural areas was much slower than in the past. “This is concerning news.”

In releasing the HealthCare.gov numbers, CMS spokesman Johnathan Monroe said that direct comparisons were not possible because enrollments are typically measured from Sunday through Saturday.

“Consistent with our aim to have a seamless open enrollment experience for consumers this year,” Monroe added, “the website performed optimally and consumers easily accessed enrollment tools to compare plans and prices during the first week.”

Lori Lodes, an Obama administration health official and co-founder of Get America Covered, said, “The administration has caused a lot of anxiety for people over the last year when it comes to health care, but there’s also been a more in-depth conversation about what Obamacare really is about.”

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