(Updated 4:55 P.M. ET, Dec. 3, with details of Pfizer supply chain issues)

The U.S. government has set a mid-December date to begin rolling out Pfizer's (NYSE: PFE) COVID-19 vaccine, but the day is merely a target for planning purposes as states get informed of their initial allocations from the existing stockpile, officials said Wednesday. Deliveries will ramp up from 40 million doses in December to 100 million in February.

A Food and Drug Administration panel of experts is scheduled to meet Dec. 10 to consider emergency use authorization (EUA) of the Pfizer/BioNTech vaccine, which received the green light from U.K. regulators Wednesday. Officials at Operation Warp Speed, the government's logistics task force led by the departments of Defense and Health and Human Services, have previously said express delivery companies will begin shipping vaccines within 24 hours of final approval.

A total of 6.4 million doses will be available in the first batch of vaccine released, with jurisdictions recently informed of their allocations based on population. The first batch of the vaccine from Moderna Inc. (NASDQ: MRNA), which is expected to receive FDA approval a week after Pfizer's, will contain 12.5 million doses, Army General Gus Parna, Operation Warp Speed's chief operating officer, said during Wednesday's press briefing.

"It is not about getting in front of an EUA, it's just making sure that we have everything locked so when the EUA decision comes, distribution to the American people is immediate," he said. "You can't execute if you don't have a plan."

Multiple news organizations, citing an Operation Warp Speed document, have said "go day" is Dec. 15.

Moncef Slaoui, chief scientific adviser to OWS, said 40 million doses are ready to be distributed this month, which will cover 20 million people. The Pfizer and Moderna vaccines require two shots spaced three to four weeks apart, respectively.

In January, 60 million doses will be available for 30 million people, and 100 million doses will be distributed in February, he said.

How that schedule will hold up is unclear after The Wall Street Journal reported Thursday afternoon that Pfizer cut its shipment forecast for this year in half after experiencing supply chain problems for ingredients. The U.K. could receive 4 million to 5 million doses by year's end instead of anticipated 10 million.

Both companies have contracts to provide the U.S. government 100 million doses, with options for further purchases.

"There's a chance that we may have more vaccine doses available in February, particularly if the Janssen vaccine gets emergency use authorization," Slaoui said.

Janssen Pharmaceutical Cos., part of Johnson & Johnson (NYSE: JNJ), has developed a one-shot vaccine that is undergoing Phase 3 clinical trials.

AstraZeneca also has a vaccine that is going through late clinical trials in the U.S. It is expected to get the results in late January and potentially file for an EUA soon after, Slaoui said. The British drugmaker is using a different technology that makes its version substantially cheaper and less temperature-sensitive, which could simplify distribution by reducing the need for specialized cold-chain infrastructure.

Scientists last week called into question the company's initial results of 90% efficacy for a half dose in trials conducted in the U.K.

Distribution plans finalized

Parna said the vaccines will be metered out each week to make sure there is enough product for the second doses and not overwhelm storage capacity in jurisdictions.

Meanwhile, states are supposed to present their final December distribution plans for the Pfizer vaccine by Friday and for the Moderna vaccine by Dec. 11.

"This way, we can ensure that we understand all the places where they want the vaccine delivered and at what quantities they want the vaccine delivered. And then we can coordinate with Pfizer to ensure those boxes are prepared and ready to be distributed upon EUA," Parna said.

Once addresses are in the system, the government's central distribution coordinator, McKesson Corp., can make final arrangements for FedEx (NYSE: FDX) and UPS (NYSE: UPS) to deliver the vaccines to administration sites.

"Every day that goes by after the initial push, additional vaccines come off the shelf because they've been certified and approved for distribution and administration," Parna said. "So, it's not a one and done. It's an initial push and then a continuous, cadenced flow of vaccine for planning and coordination and execution."

The Centers for Disease Control and Prevention is working closely with jurisdictions to recommend how best to implement their distribution plans. Some states may want to execute a hub-and-spoke model, while others may want the government to arrange delivery all the way down to doctors' offices and pharmacies, Parna said.

For each location, however, there's a minimum delivery requirement of 975 doses for the Pfizer vaccine – the amount that fits into one of its thermo coolers – and 100 doses for the Moderna vaccine, he said last week.

OWS agencies have conducted extensive rehearsals with jurisdictions to understand all possible delivery details.

During last week's briefing, Parna said Pfizer has been especially aggressive in running through scenarios for registering the product in jurisdictions, and "then they are delivering the product and walking through the administration sites to open boxes and dispense the vaccines. Through this process, they're capturing lessons learned and putting those in training product back sheets, as well as creating training videos."

Click here for more FreightWaves/American Shipper stories by Eric Kulisch.

RELATED NEWS:

Pfizer team evaluates higher shipping temperature for COVID vaccine

Solving the dry ice challenge for COVID vaccine

Big 3 US airlines gear up to transport COVID-19 vaccine

DoD planning ‘every statistical detail' of COVID vaccine distribution

COVID vaccine distribution to start as sprint, turn into marathon

Information fog hinders air cargo readiness for COVID vaccine

Air cargo's moon shot: Get COVID vaccine to the world

See more from Benzinga

• Click here for options trades from Benzinga

• Pandemic-induced Volatility Driving More Companies To Seek Visibility Solutions

• Banadian Pacific Seeks To Build Vancouver-area Transload And Logistics facility

© 2020 Benzinga.com. Benzinga does not provide investment advice. All rights reserved.