Biogen conference linked to hundreds of thousands of COVID cases


COVID-19 superspreading event

Biogen conference linked to hundreds of thousands of COVID cases

A study published yesterday in Science by researchers in Massachusetts suggests that a coronavirus outbreak linked to an international biotech conference in Boston in February is linked to more than 300,000 national and international infections with SARS-CoV-2, the virus that causes COVID-19.

The findings stem from an analysis of 772 genomes from SARS-CoV-2 nasopharyngeal samples led by scientists with Harvard, the Massachusetts Institute of Technology, and Massachusetts General Hospital (MGH). The samples were collected by the Massachusetts Department of Health and MGH from Mar 4 through May 9 and included samples from two putative superspreading events—one at a skilled nursing facility and the other at the Biogen conference, held in Boston on Feb 26 and 27.

Initial public health investigation and contact tracing identified approximately 100 cases associated with the conference. Viral sequencing of 28 conference-associated genomes revealed the presence of a single mutation (C2416T) not previously found in Massachusetts and likely introduced by a European conference attendee. C2416T and another conference-associated variant, C2416T/G26233T, accounted for more than half of the 772 SARS-CoV-2 genomes from Massachusetts.

Using the C2416T variant as a marker for tracking the spread of SARS-CoV-2 from the conference and comparing the conference-associated genomes with a dataset of 4,011 SARS-CoV-2 genomes from the United States and other countries, the researchers found that the conference-associated lineage began to appear in multiple states in early March and increased rapidly in frequency. By Nov 1, viruses containing C2416T could be found in 29 states.

The researchers estimate that a total of 245,000 cases (205,000 to 300,000) marked by C2416T occurred through Nov 1, with Florida accounting for the greatest proportion of those cases (29.2%). In addition, they estimate that 88,000 cases (56,000 to 139,000) were caused by C2416T/G26233T, which spread to 18 states and other countries.

“Because SARS-CoV-2 viruses circulating at the conference happened to be marked by distinct genomic signatures, we were able to track its downstream effects far beyond the superspreading event itself, tracing the descendants of the virus as they made a large contribution to the local outbreak in the Boston area and as they spread throughout the US and the world, likely causing hundreds of thousands of cases,” the authors of the study wrote.
Dec 10 Science study