The vaccine rollout is not going as planned so far, and has run headfirst into resource shortages and staffing issues caused by the raging pandemic.

Why it matters: The Trump administration's goal of vaccinating 20 million people by the end of year fell drastically short, raising concerns about how long it may be until enough people are vaccinated in the U.S. for life to return to normal.

By the numbers: 1.3% of the U.S. population has been vaccinated and 33% of the shots distributed to states have been administered, according to a Bloomberg analysis of CDC data.

• Operation Warp Speed has distributed 13 million doses, about 7 million doses short of its goal. About 4.3 million doses have been administered.

The state of play: State officials have given several reasons for why vaccinations have moved at a slower-than-expected pace, per the New York Times.

• The surge in coronavirus cases, hospitalizations and deaths have overwhelmed health care facilities, hindering their ability to deliver vaccines.
• Many states have reserved vaccine doses for nursing homes and long-term care facilities, slowing distribution.
• The holidays also led to reduced hours and limited staffing in clinics.

Yes, but: NIAID director Anthony Fauci said Sunday on ABC's "This Week" that he has seen "some little glimmer of hope" after 1.5 million doses were administered in the previous 72 hours, a marked increase in the vaccination rate.

In light of this slow rollout, some experts want to simply prioritize getting more shots in arms — regardless of which arms those are — as the pandemic worsens.

Driving the news: The head of Operation Warp Speed, Moncef Slaoui, said yesterday that the administration is considering halving the dose of each shot of the Moderna vaccine to double the number of people who could get it, per NYT.

And some experts are arguing that second shots should be delayed.

• "It's time to change the plan; namely, we should give people a single vaccination now and defer their second shot until more doses of vaccine become available," UCSF's Robert Wachter and Brown's Ashish Jha wrote yesterday in a Washington Post op-ed.

The Texas health department recently sent a letter to vaccine providers urging them to vaccinate as many people as possible, as quickly as possible.

• "If, in a given situation, all readily available and willing 1A and 1B persons have been served, we urge you to pivot again and provide vaccine to any additional available and willing persons, regardless of their priority designation," the commissioner wrote.

The bottom line: "A vaccine that’s sitting on a shelf for weeks, waiting for its perfect recipient, doesn’t help snuff out the pandemic," former FDA Commissioner Scott Gottlieb wrote in a WSJ op-ed.