Figure 3. Comparison of severe acute respiratory syndrome coronavirus 2 variants of concern in wastewater solids with coronavirus disease case isolates, San Jose and Sacramento, California, USA, February 1–July 31, 2021. A, B) Proportion of circulating severe acute respiratory syndrome coronavirus 2 attributable to the Alpha and Delta variants, estimated from isolate sequencing data from cases collected and sequenced over the previous 14-day period in San Jose (A) and Sacramento (B) sewersheds. C, D) Concentrations of mutations found in Alpha (HV69-70) and Delta (Del156-157/R158G) variant viruses, normalized by N gene concentrations in wastewater, averaged over the previous 14 days in San Jose (C) and Sacramento (D). No data are shown for dates for which no measurements were made within the previous 14 days. N, nucleoprotein.