AstraZeneca shelf life hurts rollout for world's poorest

The relatively short shelf life of AstraZeneca's COVID-19 vaccine is complicating the rollout to the world's poorest nations, according to officials and internal World Health Organization documents reviewed by Reuters. As vaccine production ramped up and richer states began donating excess doses, some countries - particularly in Africa – are now struggling to administer the big shipments.Olivia Chan reports.