Here's why Covid vaccines will still be free for uninsured Americans as public health emergency ends

Uninsured Americans can still access Covid-19 vaccines at no cost, for now, even though the U.S. public health emergency has ended. 

The Biden administration on Thursday lifted the 3-year-old emergency declaration, which had enabled the government to provide enhanced social safety net benefits and free Covid vaccines, tests and treatments during the pandemic. 

But the availability and cost of those vaccines are actually determined by the federal government's supply of free shots, not by the public health emergency. 

That means people with or without insurance will not have to pay out of pocket for Covid jabs, as long as that stockpile lasts.

Providers of federally purchased Covid vaccines cannot charge patients, or deny them shots, based on a person's insurance status, according to the Centers for Disease Control Prevention. 

The Biden administration ordered 171 million omicron Covid boosters last July. Since then, about 56 million omicron shots have been administered, the CDC says.

That leaves more than 100 million free shots available to the public. The government estimates that supply could last until the fall. 

"There are many, many doses still left. As you know, the booster uptake hasn't been very good," said Jen Kates, senior vice president of KFF, a health policy research organization. 

But the vast majority of Americans will not have to pay out of pocket for Covid vaccines even after the federal government's stockpile runs out. 

The government will shift Covid vaccine distribution to the private market as soon as that supply is gone.

That means vaccine makers Pfizer and Moderna will sell their shots directly to health-care providers at around $130 per dose — an almost fivefold increase over current prices.

Insured Americans will be able to access Covid shots as part of their coverage, without having to pay out of pocket.

Private insurers and the government-run Medicare and Medicaid programs are required to cover all shots recommended by the CDC.

But for uninsured Americans, federal and corporate programs are aiming to fill the gap.

There are still outstanding questions about what those efforts will look like.

Here's what we know about those programs so far:

The CDC's Vaccines For Children program will provide free Covid shots to children whose families or caretakers can't afford them after the shots move to the commercial market.

Children and teens 19 or younger who are uninsured, underinsured or eligible for Medicaid qualify for the permanent VFC program.

That program already provides free shots for other diseases, such as measles and chickenpox.

The CDC's decision to include Covid shots in the free vaccine program will be crucial to maintaining access for many children — especially those who will no longer be eligible for other programs.

As many as 5 million kids are expected to lose health insurance through Medicaid or the Children's Health Insurance Program without the public health emergency in place, according to a report last year from the Department of Health and Human Services.

The Biden administration proposed creating a permanent program similar to VFC for uninsured adults who cannot afford Covid vaccines and shots for other diseases. But Congress so far has not enacted that proposal into law.

In the meantime, the administration last month launched the "HHS Bridge Access Program," a temporary effort that will provide free Covid shots and treatments to uninsured Americans once those products move to the commercial market.

Under the arrangement, the CDC will continue to purchase Covid vaccines at a discount and distribute them through 64 state and local health departments. 

That HHS effort will leverage the "public commitments" by drug manufacturers to provide free Covid vaccines and treatments to uninsured people. HHS expects the manufacturers to directly supply shots to pharmacies for free as part of those commitments.

Kates said HHS appears to be referring to Pfizer's and Moderna's newly announced patient assistance programs, which are committed to providing free Covid vaccines and treatments to uninsured people.

"To my understanding, HHS is basically saying it will pay pharmacies the cost of administering vaccines and treatments to the public, while manufacturers will directly provide pharmacies with free vaccines and treatments as part of their patient assistance programs," Kates told CNBC. 

Pfizer and Moderna have not said whether they would supply free shots to pharmacies.

Kates said the Bridge Access Program overall will "certainly help" some uninsured Americans, but added that it is still "hard to gauge" how many people will benefit and how long the program will stay in place.

Pfizer and Moderna both intend to launch patient assistance programs for their Covid shots, but the companies have provided few details on those efforts. 

Patient assistant programs typically involve pharmacies and other vaccine providers paying a company upfront for a drug, according to Claire Hannan, executive director of the Association of Immunization Managers. 

She said those providers can then submit a reimbursement request to the program for the cost of that drug after they administer it to an eligible patient.

Pfizer's patient assistance program will allow eligible uninsured Americans to access its Covid shot for free once vaccines shift to the commercial market, according to a company spokesperson. Pfizer already has an assistance program in place for its other medicines.

The company will share further information on the assistance program's application process and eligibility guidelines when it is available, the spokesperson added.

Moderna in February said its patient assistance program would go into effect after the public health emergency ends.

The company did not immediately respond to CNBC's questions about additional details on the program.

Lawmakers and health policy experts have heavily criticized patient assistance programs for being difficult to access and understand.

A 2018 study suggested providers don't always know which patients would be best for those programs due to a lack of clear information on eligibility and benefits. 

Hannan said companies will have to ensure that people without insurance can easily access a free Covid shot through their patient assistance programs.

"If you make it challenging and make them jump through multiple hoops, vaccine uptake is probably not going to be where we would want to see it," Hannan told CNBC.