What is the volume, in ml,  of the Covid-19 vaccine?

The vaccine vial contains 0.45 mL of vaccine, pre-dilution.  At the location where it's to be administered, the technician has to add 1.8 mL of saline to dilute the vaccine to the proper level.  The vial is said to contain 6 doses of 0.3 mL each.  However 6 x 0.3 is a total of 1.8 mL, a bit short of the 2.25 mL total there would be after dilution.  That's enough for a 7th dose, but I don't know whether clinics are allowed to use that last little bit for one more dose or if they have to stop at 6 doses.

So, multiply the US population by 0.3 to get the total number of mL (which is the same as cubic centimeters), and then divide by 1,000,000 to get the total in cubic meters.  But keep in mind that the vaccine is only certified for people 16 and older, and there is a lot of population younger than that.  So you'll have to figure out exactly what number of people you want to count as the total population.