On 2021-01-22 a superspreading event most likely occurred in Michigan. 7 days later (2021-01-29) it started to super-spread through the community. A total of 63 copies of this genome (that represents the core of the outbreak), were reported in Gisaid, a proxy for primary transmissions, along with 85 genomes that are one-step mutation with respect to the core genome (a proxy for secondary transmissions). The signature for the likely superspreading event ends at about 2021-02-05, 14 days after it started, with 1603 sequences found in total.
The last sequence of the superspreading event was collected on 2021-03-06.