Dry ice can work for that. https://www.pfizer.com/news/hot-topics/covid_19_vaccine_u_s_distribution_fact_sheet https://www.pfizer.com/news/hot-topics/covid_19_v

Dry ice can work for that. https://www.pfizer.com/news/hot-topics/covid_19_vaccine_u_s_distribution_fact_sheet https://www.pfizer.com/news/hot-topics/covid_19_vaccine_u_s_... I am using "just" to mean simply rather than recently. For a wealthy government willing to spend, acquiring freezers is not a problem.