Drugstore chain CVS Health Corp said on Monday it has completed administering the first round of COVID-19 vaccination at about 8,000 U.S. nursing facilities.

Administration of second doses was underway and expected to be completed within four weeks, the company said.

CVS Pharmacy, which has administered nearly 2 million doses to date but has a capacity for 20 million–25 million shots a month, says its long-term care vaccination effort remains on track.

There have been growing concerns about a slower-than-expected rollout of COVID-19 vaccines in the country. As of Sunday, just over 18.5 million had received one or more doses of the vaccine, according to the U.S. Centers for Disease Control and Prevention. While the government had earlier expected 20 million to have been vaccinated by the end of 2020.

CVS has been administering the vaccine in long-term care facilities across 49 states. The company along with Walgreens Boots Alliance has an agreement with the federal government to vaccinate U.S. nursing home residents through a voluntary program.

The new Biden administration has set an aggressive goal of vaccinating 100 million by end of U.S. President Joe Biden's first 100 days in office.

First doses at all long-term care facilities will be complete by mid-February, CVS said, adding that through a federal partnership, COVID-19 vaccines will soon be available at CVS stores across the country.

(Reporting by Trisha Roy in Bengaluru; Editing by Shinjini Ganguli) ((Trisha.Roy@thomsonreuters.com; within U.S. +1 646 223 8780, outside U.S. +91 80 6182 3635;))