“These vials are unpredictable,” Dr. Patrice Burgess of St. Alphonsus Health System told Idaho Matters. “Sometimes they contain, for Pfizer, as many as five doses, sometimes as many as seven. For Moderna, sometimes ten, sometimes as many as twelve.” Credit Richard Villalon / Adobe Stock Complicating matters further, providers rarely know how many doses they'll get until a delivery arrives. Primary Health Medical Group CEO Dr. David Peterman said his clinics received about 2,000 first doses one week, and fewer than 1,000 the next. (Distribution of second doses automatically follows first doses on a three or four week timeline, depending on the manufacturer).