“We're going to go through stages, as we vaccinate higher and higher portions of populations, where it will make sense for us to continue to watch where vaccines are needed, how vaccines are distributed, the best way to reach more people,” Andy Slavitt, senior adviser for the White House’s Covid Response team, said at the end of March.

Meanwhile, doses pile up. West Virginia — lauded for its rollout of shots early on — has gone from using all but a tiny percentage of its supply in mid-February to 26% of doses unused, a daily average of 352,000 unused doses over the last week. Some states have never gotten their vaccination strategy in gear. Alabama, Georgia and Mississippi represent a band of southern states that have struggled to work through their supplies.

States don't control all of the distribution inside their own borders. Mississippi says it has used 77% of the doses it has requested. But when the doses sent directly by the federal government to pharmacies and other locations are counted, only 65% of doses in the state have been used, according to Bloomberg's analysis.

Taken together, the worst-performing quartile of states holds 14.1 million unused doses, meaning that 31% of doses delivered in those states are yet to be marked as used. In the best-performing quartile of states, only 11% of doses were unused.

Early in the vaccine drive, West Virginia focused on its older population and has now shifted to those in their teens to mid-30s, where most new Covid-19 cases are turning up, said Clay Marsh, the state's Covid-19 czar.

“We’re seeing more incidents of more people needing more convincing or needing more time to make their decision,” he said.  “We’re right on that interface of having more vaccine than arms to put them in.”

About 45% of Charlottesville’s 47,200 residents have received at least one dose, according to Virginia Department of Health data. Demand has remained high enough that the Blue Ridge Health District, which includes Charlottesville, restricted access.  Not until Monday did the district open eligibility to people 16 and older, in line with Governor Ralph Northam’s goal of allowing everyone in the state to get a shot by the beginning of next week.

In Lynchburg, eligibility officially opened to everyone 16 and older April 5. Even before that, restrictions weren’t much enforced. Still, only about 29% of the city’s 82,000 residents have received at least one dose, according to health department data.  If it were a state, Lynchburg’s vaccine rate would rank near the bottom, just above Alabama and Mississippi.

“At first we didn’t have enough vaccine, and now that we have a pretty good supply, the demand isn’t there,” said Kerry Gateley, health director for the Central Virginia Health District that Lynchburg falls under.

Unvaccinated pockets around the country give the virus room to spread and, perhaps worse, the ability to evolve. Experts worry that’s a perfect recipe for virus variants.