Frozen vaccine considerations
Short version- minor issue compared to pandemic
Longer version though I'm not going to elaborate too much
1) Federal or State disbursement will be in containers that may be opened twice daily to remove vaccine-- then stable 5 days in a proper medical rated refrigerator (USA)
2) Ultra cold freezer not required for every site (most do not have)
3) 25 pounds of pelletized dry ice required every 5 days, containers then returned

So definitely more of a problem for third world or logistically challenged areas