Study: Boston conference linked to spread of over 333,000 COVID-19 cases

The Biogen conference held in Boston in late February has been linked to more than 333,000 coronavirus cases, a new study in the journal Science says, calling the two-day function a "superspreader event."

Why it matters: The study estimates that the conference was behind 1.9% of all U.S. cases since the pandemic got underway, spreading to 29 states. It illustrates how a single-site event with attendees who traveled from afar can spur a national outbreak.

• The conference took place before most public health restrictions went into effect across the U.S., and therefore the virus spread more easily regionally, nationally and globally.
• The research also reveals how the virus spread among Boston's homeless population. It was then "exported to other domestic and international sites."

Details: The study estimates that the event led to around 333,000 cases worldwide, although that number may be higher.

• A second superspreader event in a Boston-area nursing facility that was cited in the report resulted in 24 residents who tested positive for the virus and died within two weeks of testing.

What they're saying: "[T]his study provides clear evidence that superspreading events may profoundly alter the course of an epidemic and implies that prevention, detection, and mitigation of such events should be a priority for public health efforts," the study says.