Use the good data
The Pitkin County Health Department, Aspen Valley Hospital, and Community Health Systems are in a good place to get specific and communicative about the planned dissemination of the COVID-19 vaccine to the Phase 1B, over-70 age group. The successful preregistration process has provided birth dates for the 1,600 registrants.
Right now, the county presumably can, should, and will sort the registrants by age, with the oldest resident at the top of the list, and the youngest 70-year-old at the bottom. Even sorting by hand should take only a few people a few hours.
The county can then inform each registrant where they stand in the line and initiate the appointments as the batches of vaccines are received. This will maintain group priorities, and lessen the confused and inefficient appointment scheduling experienced in other counties.
This sequencing is independent of when and how many doses become available to the county. Whether they trickle in over months or all come tomorrow, so be it. But the target order of actual shot-in-arm appointments should be set and known.