Where Do Vaccine Doses Go, and Who Gets Them? The Algorithms Decide

Some prioritization formulas also conflict with one another or impose such prescriptive rules that they hinder immunizations, public health experts say. Yet many Americans may not be aware of the layers of algorithms influencing their access to vaccines.

Ellen P. Goodman, a professor at Rutgers Law School who studies how governments use automated decision-making systems, said algorithms were needed to efficiently allocate the vaccines. But public agencies and health centers should be transparent about the prioritization formulas, she added.

“We want to know who is using them, what they are trying to do, who owns the proprietary algorithms, whether they are audited,” she said.

The vaccine prioritization formulas fall roughly into three tiers: federal, state and local. At the top level, Operation Warp Speed — a multiagency federal effort, created by the Trump administration — has managed nationwide vaccine distribution through Tiberius, an online portal developed by Palantir, the data-mining giant. The Biden administration, which has retired the program’s name, has taken over and is continuing the effort.

To divvy up doses, federal administrators use a simple algorithm. It automatically divides the total amount of vaccine available each week among the 50 states — as well as U.S. territories and a few big cities like New York — based on the number of people over 18 in each place.

Some health officials and researchers, however, described the Tiberius algorithm as a black box.

“Why can’t they make public the methods that they use to make these estimations?” said Dr. Rebecca Weintraub, an assistant professor of medicine at Harvard Medical School who was a co-author of a recent study on state vaccination plans. “Why are the states receiving a different number of doses than they expected per week?”

States began warning about Tiberius’s drawbacks last fall. In interim vaccine plans filed with the C.D.C., some state health administrators complained that the platform seemed overly cumbersome and that the algorithm’s week-by-week allotments would make it difficult to plan monthslong vaccination campaigns.