Vaccination is the best way to protect people from disease and save lives. It reduces new COVID-19 infections, intensive care unit admissions, and deaths, especially when it is swiftly deployed and accompanied by stringent containment measures and other preventive health interventions.

Nevertheless, vaccine deployment is slowing in the world’s poorest economies and still lags far behind richer countries. This is partly due to the fact that there are many obstacles to vaccine rollout: early vaccine procurement and domestic production are critical; a country’s severity of the pandemic, its healthcare infrastructure, and vaccine acceptance are important factors; and cross-country health spillovers mean that the pandemic won’t be over anywhere until it’s over everywhere.

Swift and broad vaccination is a critical step to global economic recovery. Vaccines not only keep people healthy and productive, they lower health care costs and boost consumer confidence. But, because of supply constraints and the risk of severe adverse reactions, governments must decide how to allocate limited supplies of vaccines among the population.

To aid in this decision, we present a new SEIRD-type model that evaluates the impact of different prioritisation strategies for vaccinating groups with limited available doses, including children. Our results show that prioritising groups with high daily interaction counts (i.e., younger groups as in the case of the COVID-19 pandemic) significantly reduces overall fatalities. However, exclusion of children dissipates these gains, so prioritising by interactions remains the best strategy.