A few weeks into her part-time job vaccinating nursing home staff members and residents against the coronavirus, Katherine, a pharmacist, noticed a problem: Roughly 15 to 20 vaccines were being thrown away at the end of each vaccination session. That’s because the number of doses that she and her co-workers had prepared — per the protocol established by Katherine’s manager at CVS, the pharmacy she works for — exceeded the number of people who showed up to be inoculated, often significantly.

Katherine — who asked to be identified by her confirmation name, because she is not authorized to discuss company matters — and her colleagues realized that if they prepared just one or two vials at a time, instead of 20 or more, as they had been doing, they could avoid wasting most doses.

“If you did it one vial at a time as people arrived, you’d never have more than five or six extra shots at the end of any clinic,” Katherine explained to me. “That’s few enough that you could find eligible recipients quickly, so you wouldn’t have […]