Planes, dry ice, pharmacies: The vaccine challenges

The United States could be the first country to launch one of the most ambitious vaccine operations in history: distributing and administering up to 600 million doses of the Pfizer and BioNTech Covid-19 vaccine in just a few months. Massive vaccine campaigns are nothing new - they have been carried out for decades in the fight against measles and flu, for example. But stamping out the coronavirus is a distinctly new challenge due to three factors: the short timeframe for inoculating a huge number of people; the fact that most vaccines will require two doses; and the very low temperature at which some of the vaccines must be stored.