COVID-19 Vaccination in California: Are We Equitable Yet?

Schmidt, A. J.; Daza Torres, M. L.; Garcia, Y. E.; Ashby, J. L.; Pollock, B. H.; Sharpnack, J.; Nuno, M.

Background. By March 2021, California had one of the least equitable vaccine distribution programs in the US. To rectify this, Governor Newsom ordered 4 million vaccine doses be reserved for the census tracts in the lowest quartile of the Healthy Places Index (HPI). California plans to lift state-wide COVID-19 restrictions on June 15th, 2021, as long as test positivity and vaccine equity thresholds are met in the state's most vulnerable census tracts. This short investigation examines current vaccine equity and forecasts where California can expect to be on June 15th. Methods. Current vaccine equity was investigated with simple linear regression between the county mean HPI and both single and full-dose vaccination rate. Future vaccination coverage per county were forecast using a compartmental mathematical model based on the average rate over the previous 30 days with four different rate-change scenarios. Results. County mean HPI has a strong positive association with both single and full dose vaccination rates (R2: 0.716 and 0.737, respectively). We predict the overall state rate will exceed 50% fully vaccinated by June 15th if the current rates are maintained; however, the bulk of this coverage comes from the top 18 counties while the remaining 40 counties lag behind. Discussion. The clear association between county HPI and current vaccination rates shows that California is not initiating opening plans from an equitable foundation, despite previous equity programs. If nothing changes, many of the most vulnerable counties will not be prepared to open without consequences come June 15th.