(CNN) Vaccines like to be kept cool, none more so than the Pfizer candidate for Covid-19 , which has to be deep-frozen. Employees fill a clinical and pharmaceutical product shipping box with dry ice at the Va-Q-Tec AG factory in Wurzburg, Germany, on November 18. The boxes will hold up to 975 vials (4,875 doses) and can be refilled with dry ice for up to 15 days of storage. Several dry ice producers in the US told CNN they've already had offers for their entire output. But Rushing cautions that dry ice is not very user-friendly and can be hazardous if stored improperly, especially in a confined space.

Source: CNN November 21, 2020 04:52 UTC