Vaccination is one of the most effective strategies to control the spread of COVID-19 and reduce morbidity and mortality; however, rapid and equitable vaccine distribution is required to achieve such outcomes. We conducted a basic interrupted time-series analysis to examine the short-term impacts of a citywide vaccine equity plan, the Protect Chicago Plus (PCP) plan. We compared vaccine coverage in zip codes in Chicago with high COVID-19 vulnerability, as identified from the Chicago COVID-19 Community Vulnerability Index, with coverage in all other zip codes in Chicago. From our analysis, we observed that implementation of PCP coincided with reduced vaccination disparities between Chicago communities with low and high vulnerability indexes over time. In our analysis of vaccination coverage before program implementation, vaccination coverage climbed nearly twice as fast among non-PCP zip codes (0.19% per day) than among PCP zip codes (0.10% per day) or by 0.09 percentage points (P < .001). In model analysis after program implementation, zip codes prioritized for the program had 0.42% additional coverage per day as compared with 0.27% per day for non-PCP zip codes. Our findings suggest that such programs may improve vaccine equity, but additional research is needed to better understand the longer-term effects of citywide vaccination strategies on vaccine uptake.
Keywords: COVID-19; community vulnerability; health equity; interrupted time series; vaccination.