Americans received just over 3 million initial doses of coronavirus vaccines from Moderna and Pfizer-BioNTech in the 19 days following first shipments, according to a Bloomberg tally of government websites and CDC data.

Why it matters: It’s far below Operation Warp Speed’s goal of administering 20 million doses by the end of the year, raising concerns about how long it may be until enough people are vaccinated in the U.S. for life to return to normal.

What’s happening: Federal officials say that 14 million doses of the Pfizer and Moderna vaccines had been distributed in the U.S. as of Wednesday morning, but that delays in actually administering the shots have occurred in the final stretch of the process, the New York Times reports.

  • Some clinics administering vaccines are on reduced holiday hours, while federal officials have left practical details of the final rollout “to overstretched local health officials and hospitals,” per the Times.
  • Some governors have also said they have not received enough funding from the federal government to support the infrastructure needed for a mass rollout.
  • Operation Warp Speed officials said at a Wednesday press briefing that they expect the vaccination process to accelerate once pharmacies offer in-store shots.

By the numbers: 0.9% of the U.S. population has been vaccinated, while just 25% of the shots distributed to states thus far have been administered, according to Bloomberg’s count (last updated Dec. 31 at 11:30am).

  • Data reported to the CDC on doses administered “significantly lags,” a Health and Human Services spokesperson tweeted Tuesday, citing “a large difference between the number of doses distributed and the number of doses administered.”

What they’re saying: Former FDA Commissioner Scott Gottlieb tweeted on Thursday that the coronavirus vaccine “could be a tool to help reduce the impact of current wave of epidemic spread; but we’re largely missing the narrow window we had to deploy it rapidly enough to alter the present trajectory of death and disease in January.”

  • Gottlieb added that the highly infectious new variant of COVID discovered in the U.K. and reported in two U.S. states this week “makes this more urgent.”
  • Moncef Slaoui, the White House’s top scientific advisor to Operation Warp Speed, told the Times: “We agree that that number is lower than what we hoped for … We know that it should be better, and we’re working hard to make it better.”
  • NIAID director Anthony Fauci told CNN on Tuesday that U.S. vaccination rates are “certainly are not at the numbers we wanted to be at the end of December” — but that he believes momentum will increase in January.

Between the lines: The Moderna and Pfizer-BioNTech vaccines both require a two-dose regimen. Pfizer warned in a statement this week that there are “no data” to prove that one dose of its vaccine will protect people from infection after 21 days, after the U.K. and some Canadian provinces shifted their strategy to prioritize giving as many single-doses as possible.

What to watch: Joe Biden aims to use the Defense Production Act to administer 100 million vaccine shots by May 1.

Go deeper: Coronavirus vaccine timelines vary widely around the world