Fig. 2

Histogram indicating the number of sequenced viruses grouping within distinct lineages introduced to Humboldt County over the course of the pandemic. For those introductions that resulted in greater than 10 post-introduction events, the Pango lineage is indicated. While the majority of introductions were limited to themselves, the largest post-introduction clade size was 222 events. The introduction resulting in 47 sequenced viruses contains the farm outbreak clade, and the introduction resulting in 222 sequenced viruses contains the SNF outbreak clade. *The parental B.1.311 lineage in this case gave rise to additional de novo mutations in Spike in some downstream members of this clade, including N501Y, and T95I