President Barack Obama appealed to uninsured Americans to sign up for medical coverage before a March 31 deadline while his administration said 4.2 million people had enrolled in health plans through February.

Youth enrollment continued to expand, with 1.1 million people ages 18 to 34 signed up by March 1, an increase of 268,475 in a month, U.S. health officials said in a report. Obama made a special effort to reach young adults yesterday, exchanging barbs with comedian Zach Galifianakis while pitching the health-care law on the actor’s parody web talk-show “Between Two Ferns.”

A survey this week found the number of uninsured dropped since Jan. 1 when plans sold on the new health exchanges took effect. About 15.9 percent of Americans lack coverage this year, down from an all-time high of 18 percent in 2013, Gallup Inc. said March 10.

“That wasn’t a coincidence or something that just happened on its own,” U.S. Health Secretary Kathleen Sebelius said yesterday in a conference call with reporters. “What we’re finding is that as more Americans find out just how affordable marketplace insurance can be, more are signing up to be covered.”

The Congressional Budget Office estimates that about 6 million people will sign up this year for private plans under the new insurance marketplaces created by the Patient Protection and Affordable Care Act known as Obamacare. Another 8 million are expected to join Medicaid, the government program for the poor that is being expanded in at least 25 states. The goal of the 2010 law is to reduce the country’s estimated 48 million uninsured.

More Anticipated

“Millions more Americans” are expected to sign up for private plans before the March 31 enrollment deadline, said Julie Bataille, a spokeswoman for the Centers for Medicare and Medicaid Services. Her agency has beefed up computer systems supporting the federal enrollment site,, in anticipation of higher traffic, she said.

Administration officials said they have no information on how many people were uninsured before they signed up under the Affordable Care Act, instead pointing to the Gallup survey and other studies by independent groups. About 27 percent of people enrolling in February were previously uninsured, according to a March 6 survey by the consulting firm McKinsey & Co.

“Until the administration provides details about who was previously uninsured and who has paid, these reports tell us nothing about the success or failure of the president’s health- care law,” Noelle Clemente, a spokeswoman for Republicans on the House Energy and Commerce Committee, said in an e-mail. “The president’s recent media appearances suggest that the administration is panicked as the March 31 deadline fast approaches.”

Life Changes