All three global VoCs (B.1.1.7, B.1.351, and P.1) have now been detected in MA. However, unlike B.1.1.7 and B.1.351, P.1 has shown a rapid rise in frequency in the few weeks following its first detection on March 16th, 2021. Phylogenetic analysis of these 54 P.1 genomes from MA, alongside four additional P.1 genomes from neighbouring states (two from Connecticut (CT) and one each from Maine (ME) and Rhode Island (RI)) and 895 other global P.1 sequences from GISAID, 6 1 suggests at least six introductions of P.1 into MA and at least eight introductions of P.1 into the New England region, likely from both international and domestic sources.
Virological.org preprint – Detection of a large cluster and multiple introductions of the P.1 SARS-CoV-2 Variant of Concern in Massachusetts
