The Food and Drug Administration (FDA) has been reviewing data to authorize a second booster dose of vaccines from Pfizer and BioNTech and Moderna, the report added.
The FDA did not immediately comment.
The agency last month cut the interval to get a booster dose of Covid-19 vaccines from Pfizer and BioNTech as well as from Moderna, in a bid to provide better protection sooner against the Omicron variant.
The planning is still in early stages and authorization would depend on determinations as to whether the second booster should be authorized for all adults or particular age groups, and whether it should target the Omicron variant or be formulated differently, the report said.
It added that no decision was final and that it could be necessary to make booster shots available earlier if a new variant appears.
The US reported 2,323 Covid-19 deaths on Friday, bringing the overall death toll to 936,523.