Cross-country health spillovers from vaccine rollouts mean the pandemic will not be over anywhere until it is over everywhere. This column argues that the success of a country’s vaccine deployment in the first half of 2021 was driven by five primary factors: the severity of its pandemic waves in 2020, its procurement strategies, the quantity of locally produced vaccines, the quality of health infrastructure, and vaccine acceptance. Swift and broad administration of vaccines provides a significant boost to health outcomes, particularly in the midst of major outbreaks and accompanied by containment measures.