• CVS Health and Walgreens said they expect to complete the first round of Covid vaccinations in nursing homes and assisted living facilities by Jan. 25.
• Vaccinating residents and staff at nursing homes and assisted living facilities is one of the first major steps in the nationwide rollout.
• CVS said it has confronted a couple of challenges during the program, including lower-than-expected uptake in staff.
• The vaccine rollout has been slower than federal officials anticipated, but CVS and Walgreens said their effort is ramping up quickly.

CVS Health and Walgreens said Wednesday they are on track to complete the first round of Covid vaccine shots at nursing homes across the country by Jan. 25.

The federal government partnered with the two pharmacy chains to administer the shots to residents and staff in long-term care facilities.

Nursing homes and assisted living facilities are at the top of the priority list for the vaccine, along with health-care workers. Vaccinations at the facilities mark one of the first major steps in the wider national rollout. Public health and state officials have prioritized the long-term care facilities because they have been especially hard-hit by coronavirus outbreaks and deaths. Less than 1% of the U.S. population lives in long-term care facilities, but they account for about 38% of all Covid-19 deaths in the country as of Dec. 31, according to COVID Tracking Project, an effort led by The Atlantic magazine.

With their updates this week, the companies offered a bright spot for a vaccine rollout that has been slower than federal officials and public health officials anticipated. The U.S. has distributed just over 17 million doses, and 4.8 million people have been given their first shot as of Tuesday — far short of the country's original goal of immunizing at least 20 million people by the end of 2020.

CVS and Walgreens began inoculations at long-term care facilities in a few states on Dec. 18. They've since expanded to thousands of facilities across 49 states, the District of Columbia and Puerto Rico. West Virginia has not opted in to the federal program for Covid vaccinations at long-term care facilities.

CVS said it has confronted a couple of challenges during the program. The actual number of residents in nursing homes was about 20% to 30% lower than projections based on bed count, the company said in a news release. And it noted that "initial uptake among staff is low," adding that part of that is likely due to facilities wanting to stagger vaccinations of staff. Facilities are spacing out employee vaccinations to avoid staffing shortages in case side effects keep some workers at home for a couple of days.

"We're dealing with a vulnerable population that requires onsite and, in some cases, in-room visits at facilities with fewer than 100 residents on average," CEO Larry Merlo said in a statement. "Despite these challenges we remain on schedule, and the number of vaccines we administer will continue to rise as more facilities are activated by the states."

While more than 3.2 million doses of vaccine have been distributed by the federal government through the federal pharmacy partnership for long-term care program, just 429,000 have been administered as of Tuesday, according to data from the Centers for Disease Control and Prevention. But CVS noted that the CDC's data lags reality by two to three days, which CDC acknowledges.

In the coming weeks, Dr. Nancy Messonnier, the director of the CDC's National Center for Immunization and Respiratory Diseases, said Tuesday at an event hosted by STAT News that she expects the wider rollout of the vaccine to speed up.

"I really expect the pace of administration to go up pretty massively in the next couple weeks," she said, adding that facilities are working out early kinks and getting comfortable handling the vaccines.

CVS, Walgreens and other drugstores and grocers have partnered with the Department of Health and Human Resources to offer vaccinations to the general public, when they're available.

Walgreens said Wednesday that it's working with states as they finalize plans for the next phase of the vaccine rollout, such as administering the shots to other high-priority groups like essential workers and people ages 75 and older.

CVS said Wednesday it's in talks with several states "to make a limited number of doses available in the coming weeks in advance of the broader rollout."

The companies' comments come after Politico reported on Tuesday that a senior HHS official said that 3,000 to 6,000 pharmacies could begin administering Covid-19 shots in the next two weeks.

— CNBC's Kevin Stankiewicz contributed to this report.