Large urban hospitals across the U.S. are rushing to buy expensive ultra-cold freezers to store what’s likely to be the first approved Covid-19 vaccine. But most rural hospitals can’t afford these high-end units, meaning health workers and residents in those communities may have difficulty getting the shots. … The vaccine has to be stored at -70 degrees Celsius. Typical freezers don’t get that cold, making distribution of this vaccine a logistical nightmare.