Moderna's vaccine authorization means the US will ship nearly 8 million doses next week - but it'll take longer than promised to vaccinate the first 20 million Americans

• The US plans to ship 7.9 million doses of coronavirus vaccines this week, to more than 3,700 locations.
• But officials with Operation Warp Speed say it will take longer than expected to get the first 20 million Americans their doses.
• The goal had been to reach the 20 million mark by year's end, but now that will take until the first week of January, according to Warp Speed's chief operating officer.
• Moderna's COVID-19 shot was authorized Friday, boosting the US vaccine supply.

US states are set to receive almost 8 million more coronavirus vaccines doses this week, But it will take longer than expected to get the first 20 million Americans their shots, federal officials said on Saturday.

Operation Warp Speed, the federal government's coronavirus vaccine initiative, is in charge of securing doses and shipping them to states. The first shipments were completed last week, with 2.9 million doses of Pfizer's vaccine arriving at more than 600 sites across the country.

On Friday, the FDA authorized a second COVID-19 vaccine, from Moderna, for emergency use. That greatly boosts the US's vaccine supply.

That authorization means the government can ship 7.9 million total doses of Pfizer's and Moderna's vaccines to more than 3,700 sites across the country, General Gustave Perna, a co-leader of Operation Warp Speed, said Saturday.

Read more: How the pharma giant Pfizer teamed up with a little-known biotech to develop the first authorized coronavirus vaccine in record time

All told, the US is likely to distribute well over 10 million vaccine doses by Christmas. But it seems increasingly unlikely Warp Speed will meet its goal of giving 20 million Americans their first dose before the year's end.

Perna said Saturday the latest plan is to allocate 20 million doses by the end of 2020, but the process of actually shipping and distributing them will stretch into the first week of January.

The four-star general also apologized and took personal responsibility for widespread confusion that arose among state officials this week as to how many doses they'll receive. Perna said he gave planning estimates that were too high, which meant some states will receive 30% or 40% fewer doses of Pfizer's vaccine than previously expected. That has forced states to scramble to adjust their prioritization plans.

'The beginning of the end'

Officials have framed the rollout of COVID-19 vaccines as "the beginning of the end." By prioritizing the most exposed and vulnerable people - frontline healthcare workers and nursing home residents - experts hope the shots can start making an impact on the pandemic's trajectory in the coming weeks and months.

But even with vaccines progressing swiftly, the pandemic is at its worst point ever in the US. The country has been averaging more than 200,000 new infections and 2,500 deaths per day over the last week. More than 17 million people in the US have been infected since the start of the pandemic, and more than 310,000 Americans have died.

Saturday's adjustment to the vaccine timeline was not the first time Warp Speed has failed to meet its own lofty aims. The initiative launched in May with the goal of delivering 300 million doses by the end of 2020. Over time, officials have quietly walked that number back.

In August, Alex Azar, Secretary of Health and Human Services, lowered the year-end projection to "the high tens of millions of doses."

Then earlier this month, the vaccination target was lowered to 20 million - less than 10% of the original goal.

Now, it appears Warp Speed may fall slightly short of that figure. Since 2.9 million doses were shipped last week, and 7.9 million more are set to ship this week, the initiative would need to deliver 9.2 million doses in the final week of December.

But that doesn't account for the time it takes to administer the vaccine, a responsibility that falls to state and local leaders.

Read more: Meet the 19 key scientists, executives, and leaders responsible for pushing coronavirus vaccines across the finish line

Warp Speed isn't yet providing data on how many Americans have been vaccinated. Azar said on Wednesday that officials are working to set up a public dashboard with real-time information on allocation and immunization decisions, but it's unclear when that will go live.

Pfizer's and Moderna's vaccines are both two-dose regimens that have shown overwhelming effectiveness at preventing symptomatic COVID-19 in large clinical trials. Warp Speed officials kept half the available supply out of the first shipments in order to ensure that everyone who gets a shot in this first round has access to a second dose.