Nov 12 (Reuters) - The U.S. government is partnering with regional pharmacy chains and independent community pharmacies to increase access to COVID-19 vaccines whenever they are made available, the U.S. Department of Health and Human Services said on Thursday.

The partnership will cover about 60% of pharmacies throughout the 50 U.S. states, the District of Columbia, Puerto Rico, and the U.S. Virgin Islands, the U.S. health agency said.

Walgreens Boots Alliance Inc, CVS Health Corp , Walmart Inc, Kroger Co and Costco Wholesale Corp are among the companies that have so far agreed to participate, the U.S. agency said in a statement.

The vaccines will be administered at partners' pharmacy locations at no cost to patients.

"We are leveraging the existing private sector infrastructure to get safe and effective vaccines supported by Operation Warp Speed into communities and into arms as quickly as possible with no out-of-pocket costs," HHS Secretary Alex Azar said in a statement.

Currently, there are no COVID-19 vaccines that have been authorized or approved by the U.S. Food and Drug Administration.

On Monday, Pfizer Inc and German partner BioNTech <SE 22UAy.F> said their experimental COVID-19 vaccine is more than 90% effective based on initial trial results. (Reporting by Mrinalika Roy in Bengaluru; Editing by Shailesh Kuber)