A 12-year old girl receives the Pfizer-BioNtech vaccine in New York City on May 14th, 2021.Adam Jeffery | CNBCHalf of Americans aged 12 and older are now fully vaccinated, according to data published by the Centers for Disease Control and Prevention on Tuesday. The CDC signed off on expanded usage of Pfizer and BioNTech’s Covid-19 vaccine for 12- to 15-year-olds in mid-May, widening the age range of the population eligible for a shot.The seven-day average of daily U.S. infections held below 15,000 as of Tuesday, according to data compiled by Johns Hopkins University, a level not seen since the early days of the pandemic.U.S. share of the population vaccinatedAbout 52% of the U.S. population has received at least one dose of a Covid vaccine and 42% is fully vaccinated, CDC data shows.Those numbers jump to 61% with one shot or more and 50% fully inoculated for the eligible 12 and older population.Zoom In IconArrows pointing outwardsOn Tuesday, White House chief medical advisor Dr. Anthony Fauci said that more Americans need to get vaccinated in order to avoid the Delta variant becoming the dominant strain in the U.S. after the variant surpassed the Alpha strain in new infections in the United Kingdom.U.S. vaccine shots administeredThe U.S. is reporting just over 1 million shots per day on average over the past week, according to the CDC.Zoom In IconArrows pointing outwardsThough the pace has ticked upward in recent days — which may represent a rebound from a dip over Memorial Day weekend — average daily shots have been falling somewhat steadily from peak levels in mid-April. At that time, the country was reporting more than 3 million daily vaccinations.U.S. Covid casesAbout 14,400 daily cases are being reported in the U.S. on average over the past week, Hopkins data shows. That figure is down 17% from a week ago.Zoom In IconArrows pointing outwardsIn a sign of the changing nature of the outbreak, Florida and Alabama will no longer report daily Covid cases and fatalities as vaccinations rise and states begin shifting to the “next phase” of the pandemic.U.S. Covid deathsThe U.S. is reporting 427 daily Covid deaths, based on a seven-day average of Hopkins data.Zoom In IconArrows pointing outwardsMore than 598,000 total deaths have been reported in the U.S. over the course of the pandemic.