(Bloomberg) -- Weeks before states expect to receive their first shipments of Covid-19 vaccines, conflicting messages from the federal government have obscured exactly how many doses may arrive.

Some governors, including New York’s Andrew Cuomo and California’s Gavin Newsom, have made splashy announcements about how much of Pfizer Inc. and BioNTech SE’s vaccines they expect should the U.S. Food and Drug Administration authorize them this month. Other states can’t provide a solid answer given how quickly estimates change.

But all must submit orders and distribution plans Friday, and the shifting expectations compound other complications. States must find dry ice to store finicky formulas that require delicate timetables to administer. They must decide how to get the shots to residents equitably. And they must do so using a public-health infrastructure withered after decades of underfunding and neglect. At stake is an efficient escape from the deadliest pandemic in a century.

“States are throwing their hands up figuring out the math, and are saying, ‘Just tell me the amount and stay with it,’” said Claire Hannan, executive director of the Association of Immunization Managers.

Officials of Operation Warp Speed, the Trump administration’s project to accelerate vaccine creation, told states in late November their expected allotment of doses for December. Officials said the total supply would be 6.4 million of the Pfizer vaccine and 12.5 million of Moderna’s shot.

The goal is to send initial shipments immediately after FDA authorization, with fresh doses delivered in weekly installments after that. The first batches are expected to arrive in states as soon as mid-December.

The government has said the first batch will be divided among 69 entities -- states, territories, large cities and the departments of State, Defense, Veterans Affairs, the Bureau of Prisons and the Indian Health Service. They are to be allocated using an apparently straightforward calculation: their proportion of the adult population.

“It’s pro rata,” Army General Gustave Perna, chief operations officer of Operation Warp Speed, said in a Wednesday briefing. “It’s a math problem in execution.”

But Natalie Baldassarre, a spokeswoman for the Department of Health and Human Services, declined to say how many doses are allocated to each entity or how agency allotments would be calculated. Spokespeople for the departments declined to provide the number of vaccines they expect or didn’t respond to requests for comment.

The Indian Health Service “will work within the amount allocated,” and hopes to vaccinate half its health-care personnel, said spokesman Joshua Barnett.

Shifting Figures

Few states contacted by Bloomberg News could provide an accurate estimate.

Michigan, for example, heard several different numbers in the past few days, everything from a couple hundred thousand to under 90,000, Health Department spokeswoman Lynn Sutfin said in an email.

California is counting on Pfizer, Newsom said at a Thursday news conference. “We have all the confidence the 327,600 doses will be made available,” he said, but added that officials remain in “advanced conversation” with Moderna.

States lack a solid grasp on the federal calculations, said Marcus Plescia, chief medical officer of the Association of State and Territorial Health Officials.

“It’s not highly transparent, I will say that,” Plescia said.

Wisconsin is lobbying for special help. Democratic Governor Tony Evers said in a briefing Thursday that Republican lawmakers have hindered the response and created a disaster. He wants enough doses to vaccinate all 450,000 of the state’s health-care workers, more than seven times the 60,000 he expects at the outset.

“Wisconsin is uniquely facing challenges,” Evers said. “We are asking the federal government to prioritize distributing vaccines in Wisconsin.”

Delicate Cargo

Wherever it goes, distributing Pfizer’s still-experimental vaccine requires careful logistical coordination. Vials will come from warehouses in Illinois and Wisconsin and will be accepted in most states at hospitals that have rare ultra-cold freezers, said Tinglong Dai, an associate professor of operations management at the Johns Hopkins Carey Business School. The shots must be kept at 94 degrees Fahrenheit below zero.

In Alabama, which expects a little more than 40,000 doses, just eight hospitals will receive the vaccine initially, all in urban areas, said Assistant State Health Officer Karen Landers. New Jersey plans to accept its Pfizer vaccines -- enough for 130,000 people -- at about 40 hospitals. They will go from there to smaller hospitals, health departments and medical providers.

As the vaccine moves out to hospitals without cold storage, things get dicier, Dai said. It will arrive in trunks filled with as many as five “pizza boxes” containing dry ice. Each will have 195 vials of five doses, for a total of 975 shots. Smaller hospitals or health departments may store the vaccine in those boxes.The dry ice must be replenished upon arrival and again in 10 days, said Dai. Once a pizza box is opened, all 975 doses must be used within five days. The boxes can be opened only twice a day and only for a minute at a time. And once a vial is opened, its five doses need to be used in six hours.“It leaves very little room for error,” said Dai. “The challenge here is making the real-life hospital situation work. Who is going to keep track of how many times the box is opened? There are so many opportunities for mistakes.”

Smoothing Bumps

Practice shipments of empty vaccine containers and mock supply kits identified hiccups in distribution. Some states didn’t receive the kits at all.

North Dakota got the trial vaccine shipment, but not the supplies, Molly Howell, its immunization program manager, said Tuesday. Colorado’s mock supply kit went to another state because of a label-printing error, officials said in a press release Tuesday.

Drug distributor McKesson Corp. is responsible for creating and sending the kits, which include supplies like masks and syringes.

“This was part of the normal process,” spokesman David Matthews said in an email. “We have addressed the issues that were identified and confirmed.”

Small Batch

The difficulty of handling the vaccines and Pfizer’s minimum order of 975 doses threaten to aggravate the divide between urban areas and rural ones that can’t dole them out fast enough.

“The logistics are not easy,” said Tim Size, director of the Rural Wisconsin Health Cooperative. Rural providers are lobbying Pfizer for smaller lots.“We have just come through a very divisive national election,” said Size. “We need to show everyone that urban and rural can work together as opposed to, ‘Oh, let’s just let the rural areas wait.’”

Despite the challenge of inventing a distribution system even as thousands fall sick each day, the initial phase could be the easiest, said Hannan of the Association of Immunization Managers. Hospitals will vaccinate their own workers. Pharmacy chains Walgreens Boots Alliance Inc. and CVS Health Corp. will vaccinate residents of nursing homes and other long-term care facilities.

More challenges could emerge when states begin vaccinating the masses, which could happen quickly as manufacturing ramps up, she said.

“You could get 100,000 doses, you could get 1 million doses,” she said. “Are you ready for 1 million doses?”

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