The distribution of a COVID-19 vaccine in the U.S. hit its first speed bumps, officials said Dec. 16. First, four delivery trays of the Pfizer-BioNTech vaccine were pulled back from delivery to California and Alabama this week and sent back to the company because they were colder than anticipated. Each of the trays likely can be used to vaccinate 975 people, so four trays equals 3,900 people. And second, the officials said about 2 million doses of the vaccine will be allocated for the U.S. next week, which is less than the 2.9 million available this week when the first shots shipped. No explanation was given for why fewer doses were going out.

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