schwit1 shares a report from The Boston Globe: A new study estimates the Biogen conference held at Boston’s Marriott Long Wharf hotel in February played a far greater role in spreading the coronavirus than previously thought. The research team analyzed the genetic sequences of the virus that caused COVID-19 in the 772 patients, almost all from Essex, Middlesex, Norfolk, and Suffolk counties. By examining mutations in the genetic code that naturally occur as the virus makes copies of itself — subtle changes that act like a passport stamp showing where the pathogen has been — the sleuths identified more than 80 distinct SARS-CoV-2 genomes of viruses that infected the Boston area in the first five months of the year. Most of the viruses came from elsewhere in the United States and Western Europe, the scientists said. But one virus with a unique genetic signature had an outsize impact. Some 289 of the 772 patients, or more than a third, were infected with a virus traceable to the meeting held on Feb. 26-27 by Cambridge biotech Biogen. In a remarkable sign of how the virus can spread unpredictably and take a disproportionate toll on society’s most vulnerable members, the 289 conference-related cases included 122 people living in Boston-area homeless shelters and employees who work there, the study says. It’s unclear what path the virus took to get there. By multiplying the proportion of conference-related viral genomes in each of the four counties by the total number of coronavirus infections in Essex, Middlesex, Norfolk, and Suffolk, the scientists estimate that 20,000 infections could be linked to the Marriott event. The study never mentions Biogen by name. It simply refers to an “international business conference held in Boston from February 26-27.” “We never would have knowingly put anyone at risk,” it said in a statement. “When we learned a number of our colleagues were ill, we did not know the cause was COVID-19, but we immediately notified public health authorities and took steps to limit the spread.” Read more of this story at Slashdot.