70% of the world could be vaccinated this year

The big picture: Many wealthy countries including the U.S. have taken a nationalistic approach to vaccine doses, which has fueled a huge gap in supply.

What they're saying: "Alongside the challenge of vaccine nationalism, our work highlights that manufacturing and supply issues remain the critical barriers," Andrea Taylor, lead researcher for the Launch and Scale Speedometer program, said in the analysis.

• "There is very little transparency in the landscape, so it is difficult for country leaders to assess the feasibility of delivery schedules or to understand the risks and contingencies.”