Bronwyn MacInnis - December 2, 2020

Bronwyn MacInnis, PhD, Director of Pathogen Genomic Surveillance, Infectious Disease and Microbiome Program, Broad Institute, United States, "Phylogenetic analysis of SARS-CoV-2 in the Boston area: disparate consequences of importations and superspreading events"

Dr. MacInnis’s work is focused on defining the transmission of SARS-CoV-2. Particularly, this work was focused on transmission in Massachusetts with data biased towards cases in Boston in 800 SARS-CoV-2 genomes from March-May. They found that in the first wave of the outbreak in March and April that transmission was associated with congregate living settings and high-risk communities. They also noted that the virus was introduced from Europe and that recurrent introduction of the virus was prevalent in the Northeastern United States. This was most likely due to lack of enforcement of border closures and quarantines. Of note, most cases did not result in onward transmission, but a small number of super-spreaders cause much of the transmission and disease burden. For example, an international business conference in late February was associated with one super-spreader case that seeded 30% of all cases in Massachusetts and lead to transmission across the United States and the world. Their work underscores the importance of testing and contact tracing to intervene and break the chain of transmission in these super-spreading events.