https://www.scientificamerican.com/article/who-will-get-covid-vaccines-first-and-who-will-have-to-wait1/

Vaccines against COVID-19 have arrived with unprecedented speed. At least three candidates appear to be extremely effective and are likely to be approved in the U.S. in coming weeks. By the end of December, the U.S. Centers for Disease Control and Prevention (CDC) estimates the U.S. will have enough vaccines to treat 20 million people. Britain this week approved the vaccine made by Pfizer and BioNTech.

But for the first time in modern U.S. history, not everyone who wants a vaccine will be able to get one immediately. Figuring out who gets the first shots in that country and who has to wait is the job of an obscure CDC panel known as the Advisory Committee on Immunization Practices (ACIP). This week they announced their first official COVID vaccine distribution guidelines.