I know this is probably a stupid question but do doctors have just certain shots or can they administer any that you want?
I work at a place that has administered approximately 4,400 vaccines thus far and have been pretty involved with the process.
Most places try to schedule only one type of vaccine each day, what kind they have depends on what their practice ordered. Seems like most places around here have both Moderna and Pfizer, with Pfizer being the most prevalent.
The vaccines have to thaw out, and each vial does multiple doses (10 for Moderna though that will be increasing, 6 for Pfizer) and expires after a certain number of hours. So preferably the try to schedule within multiples of 10 or 6, depending on which vaccine they are doing that day, to try to eliminate wasted doses.
Plus only doing one type of vaccine per day reduces potential errors like giving someone the wrong kind and makes it easier to schedule the second doses since Moderna is a 4-week wait and Pfizer a 3-weke wait. You can just pick one day and tell people to come back on this day without having to think about it any at all.
It would really make running a vaccine clinic a complete cluster*uck if we were administering both Moderna and Pfizer on the same day.
When people get their first does, we sign them up on a day that can fit into the schedule we are running. If that day is Moderna then they get Moderna, if it's Pfizer then they get Pfizer. They don't get to show up and be like "well I want Pfizer" when we are doing Moderna that day.