The United States has administered 399,552,444 doses of COVID-19 vaccines in the country as of Thursday morning and distributed 482,326,275 doses, the US Centers for Disease Control and Prevention said.
Those figures are up from the 398,675,414 vaccine doses the CDC said had gone into arms by Wednesday, out of 480,427,985 doses delivered.
The agency said 216,268,034 people had received at least one dose, while 186,618,184 people were fully vaccinated as of 6am ET on Thursday.
The CDC tally includes two-dose vaccines from Moderna and Pfizer/BioNTech, as well as Johnson & Johnson's one-shot vaccine.
About 6.8 million people received a booster dose of either Pfizer or Moderna's vaccine since Aug 13, when the US authorised a third dose of the vaccines for people with compromised immune systems who are likely to have weaker protection from the two-dose regimens.