WASHINGTON, D.C. — Federal health officials on Friday unveiled a plan to get yet-to-be-approved coronavirus vaccines to nursing home residents free of charge, enlisting two national pharmacy chains to help.

Such a vaccine is not yet available, and that led to skepticism from some long-term care experts. The distribution program is contingent on the Food and Drug Administration authorizing a vaccine, which does not appear to imminent.

Under the voluntary program, trained staff from CVS and Walgreens would deliver the vaccines to each nursing home and administer shots. Assisted-living facilities and residential group homes can also participate. Nursing home staffers can be vaccinated, too, if they have not already received their shots. Needles, syringes and other necessary equipment will be included.

The idea is to give hard-pressed states an all-inclusive system for vaccinating their most vulnerable residents, said Paul Mango, a senior policy adviser at the Department of Health and Human Services. “We are trying to eliminate all potential barriers to getting folks safe and effective vaccines,” Mango said.

Counting nursing homes and other kinds of group residences, the nation has more than 22,000 facilities.

People in nursing homes and other long-term care settings account for less than 1% of the U.S. population, but they represent about 40% of the deaths from COVID-19, with more than 83,600 fatalities logged by the COVID Tracking Project.

The Trump administration’s initial attempts to promote coronavirus testing in nursing homes and to ensure sufficient supplies of protective gear were hampered by missteps and led to widespread complaints from nursing home operators and advocates for older people. The vaccine program seems designed to prevent more problems at a time when President Donald Trump is battling to hang on to support from older voters.

Earlier this month, the National Academies of Sciences, Engineering and Medicine recommended that the initial, limited doses of vaccine should go to first responders and high-risk health care workers. Those next in line should include older residents of nursing homes, the National Academies said, noting that who gets the shots will depend on age guidelines determined by the data on vaccine safety and efficacy.

There are many unanswered questions about the vaccines now undergoing clinical trials, including how well they will work to prevent infection. It’s also not known whether they will be equally protective for older adults, as pharmaceutical companies generally test their products on younger people.

Dr. Christian Bergman, medical director of a nursing home in Richmond, Virginia, said he is pleased the government has a plan for rapid deployment of vaccines, but he needs to see clinical data before any of his patients get shots.

“I await public release of all data concerning safety and efficacy,” Bergman said. “Without this data, I will not be able to ethically endorse this vaccine and promote it within my nursing home.”

The vaccination plan for nursing homes has been set up under the auspices of Operation Warp Speed, a White House-backed campaign to quickly produce and distribute hundreds of millions of doses of approved vaccines, enough for every American. The goal is to shrink the production timetable from years to months. The effort involves HHS and the Defense Department, as well as drugmakers and other private companies.

Mango said he anticipates that if a vaccine is approved this year, initial supplies will be limited. Availability will improve markedly in the first three months of 2021, he said.

HHS is fielding an online survey for nursing homes to assess their interest in the vaccine distribution program, but the allocation of vaccines will be done through state and territorial governments.

Officials are bullish on the plan, saying vaccines will be on their way to nursing homes within 24 to 48 hours after FDA approval.

Nursing homes and long-term care facilities will not be charged for the program. CVS and Walgreens will be reimbursed for administering the shots at standard Medicare rates, officials said.

The use of retail pharmacies like CVS and Walgreens has prompted some concerns, because nursing homes typically deal with specialized pharmacies and not retail operations.

Michael Wasserman, a geriatrician and past president of the California Association of Long Term Care Medicine, said chain retail pharmacies “don’t necessarily have any clue what it takes to deliver pharmaceuticals to nursing homes. There are long-term care pharmacies that do this all the time ... Every nursing home in the country has a consultant pharmacist assigned to that facility.”

Mango said the plan would accommodate nursing homes that want to continue to work with specialized pharmacies.

HHS Secretary Alex Azar said the goal of the partnership with CVS and Walgreens is to provide convenient and free vaccination to nursing homes across the country.