The slow start to the COVID-19 vaccine rollout in the United States has been no secret: Seniors have waited in long lines for a dose, vaccine registration websites have crashed and public health resources were tied up during the country’s biggest surge yet in early January.

But health officials say that while current vaccine supply levels still limit how many vaccines they can administer, states are becoming more efficient at immunizing people as shipments arrive.

On Jan. 1, just a quarter of vaccine doses delivered across the country had been used, compared to 68% of doses on Feb. 11. A handful of states have administered more than 80% of the doses they have received. And even states with slower vaccine uptake are making strides. Alabama, for example, where the share of doses used has consistently ranked among the country’s lowest, is in the process of opening new mass vaccination sites in eight cities.

“Every state is improving,” said Claire Hannan, executive director of the Association of Immunization Managers. “We still don’t have enough to vaccinate everyone over 75, so it doesn’t necessarily feel different for people who are trying to find the vaccine, but we are in a much better place now.”

Health officials acknowledge that it’s confusing to suggest that overall supply is limited, when federal data shows that many shots still seem to be sitting unused. But jurisdictions have said that they are working around the clock to close the gap between doses delivered and administered.

For example, a federal program to vaccinate long-term care facility residents and staff has seen delays and lower-than-expected demand — leaving thousands of doses earmarked for the program unused. Some state health officials have said that they are putting those doses back into the general supply.


“As a result of that overcommitment to the program in the early weeks, states appear to have more doses within their possession than they in fact do,” said Dr. Nirav Shah, director of the Maine Center for Disease Control and Prevention. Shah noted that Maine is redirecting some of these doses to independent pharmacies.

Experts also caution that the multistep process of performing and recording vaccinations means 100% administration is an unlikely bench mark. There will always be some vaccines that haven’t been unpacked yet and others that have already been administered but not yet reported to the state and federal data systems.

It is also standard to keep some vaccine doses in inventory, especially as jurisdictions work to equip mass vaccination sites, which are ramping up across the country and are expected to further speed up the number of people getting shots.

Federal and state officials have also acknowledged that second doses have been sitting unused at some provider sites, either held up by delays in first vaccinations or reserved because providers are worried that there won’t be enough supply to ensure a second dose.

The vaccines in use in the United States, manufactured by Pfizer-BioNTech and Moderna, require patients to receive two doses spaced 21 days and 28 days apart, respectively. Vials of the vaccine are not denoted as first or second dose and can be used for either, but states order the doses separately from the federal government at intervals to ensure timely arrival.

The Biden administration recently announced plans to give states more advance notice about the doses available to them each week, to allow jurisdictions to better plan for clinics and to build confidence that enough doses are in the pipeline to provide people with their second dose.


And federal data shows that the administration of second doses is on the rise.

As states turn to balancing first and second doses, the vaccination ranking data becomes more complicated.

“There’s no good place to take a snapshot of this very, very fluid process, so it’s frustrating for states when people focus on those numbers,” said Dr. Michelle Fiscus, a medical director at the Tennessee Department of Health.

“The data doesn’t show what we’re busy doing, which is getting second doses into arms,” Fiscus said. Tennessee, which was seventh in the nation in first-dose administration on Jan. 4, has dropped to 47th in the first-dose rankings as demand for second doses has risen.

Some officials, including Fiscus, also caution that speed hasn’t been — and shouldn’t be — the country’s only priority for the rollout.

“It’s important to note that although velocity remains a goal of all the states and territories, equity is just as important of a goal,” said Shah.