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Pro Rata Vaccine Distribution is Fair, Equitable

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While COVID-19 vaccines roll out in limited supply, distribution is determined in direct proportion to the nation's adult population 18 years and older. The pro rata method was approved Nov. 6, 2020, by Health and Human Services Secretary Alex Azar. 

A woman uses a syringe to extract liquid from a small bottle she's holding upside down.
Vaccine Prep
Five military medical treatment facilities are participating in a Phase 3 clinical trial of a COVID-19 vaccine in development with AstraZeneca in Falls Church, Va., Nov. 17, 2020.
Photo By: Air Force Staff Sgt. Joshua Garcia
VIRIN: 201117-F-FT687-003A

"We considered several approaches before determining the pro rata method would result in the most fair and equitable division of available vaccines," Operation Warp Speed Chief Operating Officer Army Gen. Gus Perna said. 

Operation Warp Speed covers 50 states, eight territories and freely associated states, six metropolitan cities and five federal entities identified by pre-existing vaccine dissemination infrastructure determined by the Centers for Disease Control and Prevention. 

Official population data establishes the foundation for both initial and ongoing allocations. 

"Vaccine manufacturing continues, and each week, we will allocate additional vaccine doses based on availability and divided by the population," Operation Warp Speed's Chief of Plans, Operations and Analytics Deacon Maddox said.

New allocations will be made available to jurisdictions and agencies each Friday and uploaded into Operation Warp Speed's Tiberius software platform. Tiberius is the system of record that computes the allocations, which are visible to state, territory and agency health officials and providers who are enrolled in the CDC's Vaccine Tracking System, or VTrckS.  

The Tiberius algorithm that determines allocation is simple, Maddox explained. The team inputs risk-adjusted manufacturing estimates, a small portion is subtracted to provide a "safety stock," and the remainder is divided by population. The safety stock reserves about 5% of doses off the top that act as a buffer to account for uncertainties or issues that arise as the delivery plan is executed.   

Population numbers for the states and metropolitan areas were derived from the American Community Survey as published by the U.S. Census Bureau using a 2018 data release. Populations of the U.S. territories — American Samoa, Federated States of Micronesia, the Commonwealth of the Northern Mariana Islands, the Republic of Palau, the Republic of the Marshall Islands, Guam and the U.S. Virgin Islands — came from the Central Intelligence Agency's World Factbook. 

Two containers of a potential vaccine are in the forefront while several more are in the background in a tray.
Vaccine Vials
A potential COVID-19 vaccine is currently in the testing stage in New Orleans, Sept. 28, 2020.
Photo By: Courtesy of Johnson & Johnson
VIRIN: 201028-F-FT687-001P

The five federal entities include the Defense Department, Veterans Health Administration, Indian Health Service, State Department and Bureau of Prisons. 

While four of the five federal entities provided their own population estimates, Operation Warp Speed's leadership approved a final working figure for the Defense Department population to account for active duty service members, their family members, military retirees and DOD civilians. 

"The diverse DOD population overlaps with other federal agencies, including the Veterans Health Administration and the states," Perna said. "In this case, we used an approximation to maintain our goal of fair and equitable distribution."

Like any complex plan, Operation Warp Speed made some allowances where it made sense, Maddox explained. 

One such decision involved allocations to the Indian Health Service and the potential for inequity within tribal populations. Indian Health Service determined its population by polling 706 Indian Health facilities nationwide, asking each to decide whether to receive vaccines from the agency or their resident state. 

"We identified the potential for imbalance where tribal populations opted to receive vaccines from the state where they reside," Maddox said.
As a remedy, Operation Warp Speed created a "sovereign nation supplement" for those states with Indian Health centers that did not choose to affiliate with Indian Health Service. The solution adds a pro rata calculation to those states based on the state-supported Indian Health centers. 

Geographically isolated areas, such as Alaska, American Samoa, Guam and the Northern Mariana Islands, may order up to their monthly allocation in advance, to be delivered in the first shipment of the month. For some locations, the delivery includes both first and second doses of the two-shot vaccines.

A person in a medical uniform holds two beakers of pinkish liquid.
COVID Studies
A scientist with the Emerging Infectious Disease branch at the Walter Reed Army Institute of Research conducts studies to find a vaccine for COVID-19, July 7, 2020.
Photo By: Shawn Fury, Army
VIRIN: 200701-O-IL961-084

"Where it makes sense, we have made some conciliatory decisions — and in those cases, it is beneficial both from a distribution and recipient perspective," Maddox said.    

Once vaccines are allocated, it is up to each jurisdiction or agency to place orders, designate delivery points, prioritize recipients and administer vaccines to the American people. 

"We have empowered governors and agencies to make the most critical decisions because they know their people, their challenges and how to best serve their communities," Perna said.

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