COVID-19 Vaccine Rollout Plans Should Consider Spatial Distribution of Age-Specific Population

In the early phases of COVID-19 vaccine distribution, most countries adopted age-based rollout plans due to vaccine shortages. The plans, however, might overlook different spatial distributions of each age group. In this study, we first examine separate spatial accessibility to vaccine sites varying by different age groups, transportation modes, and times to find differences in spatial patterns of accessibility scores based on the enhanced two-step floating catchment area method. We also investigate spatial inequality in measured accessibility through the Gini coefficient. Finally, we scrutinize to what extent spatial accessibility to vaccine sites is overestimated or underestimated by different age groups. Results showed that there is spatial disparity in accessibility scores between the total population and multiple age-stratified groups. We also found that transportation modes play a significant role in determining spatial patterns of accessibility to vaccine locations, whereas time was not a major factor making differences in spatial accessibility patterns. Our findings suggest that vaccine rollout plans should incorporate age-specific population distribution to maximize accessibility and minimize spatial disparity.