A Biogen medical conference in late February led to between 205,000 to 300,000 COVID-19 infections from February to November of this year, according to a study in the peer-reviewed journal Science by the American Association for the Advancement of Science.... ...In the four counties that comprise the Boston region, 51,000 - about half - of the cases of COVID-19 until the beginning of November had genetic markers that linked the cases to the conference, according to the report. The virus also spread from the conference to other states at the beginning of...