The longest mile in the COVID-19 vaccine cold chain Current COVID-19 vaccine candidates require storage at between eight and minus 80 degrees Celsius. Cold chain infrastructure in many developing countries struggles in the 'last mile'. Copyright: UNICEF/Michael Tsegaye, (CC BY-NC-ND 2.0). This image has been cropped. Speed read Covering the ‘last mile’ of vaccine delivery remains big hurdle in COVID-19 battle Better cold chain technology can prevent up to 25 per cent vaccine loss in poor countries But rich nation ‘vaccine nationalism’ may undermine global delivery plans Share this article: Republish We encourage you to republish this article online and in print, it’s free under our creative commons attribution license, but please follow some simple guidelines: