About 175 executives were expected at the Biogen leadership conference on Feb. 26. Employees from Biogen locations around the United States and the world reunited with colleagues they don’t often get to see.

It opened with breakfast, at 7 a.m., in the Harbor View Ballroom of the Boston Marriott Long Wharf hotel, where a wide bank of windows offers a sublime view across the inner harbor, steel gray on a cloudy morning, to Logan Airport in the distance.

This story was reported by Andy Rosen, Hanna Krueger, Kay Lazar, Jonathan Saltzman, Liz Kowalczyk, and Mark Arsenault of the Globe staff. It was written by Arsenault.


They greeted each other enthusiastically, with handshakes and hugs, and then caught up over breakfast, picking from plates of pastries and the self-serve hot food bar. They were there for two days of discussions and presentations about the future of the Cambridge-based, multinational biotech firm, which develops therapies for neurological diseases. It was the kind of under-the-radar gathering that happens in this region just about every week.

Within days, though, the Biogen conference would be infamous, identified as an epicenter of the Massachusetts outbreak of Covid-19, with 70 of 92 coronavirus infections in the state linked to the conference as of Tuesday night, including employees and those who came into contact with them. That doesn’t include a cascade of individual cases in Tennessee, North Carolina, Indiana, New Jersey, Washington, D.C., and Norway, and suspected cases in Germany, Austria, and Argentina.

The virus raced through this two-day conference at a frightening speed that state health officials and company executives were unable to match. As one of the biggest and best-known biotech firms in Massachusetts and public health authorities in one of the nation’s premier medical communities struggled to connect the dots, dozens of Biogen employees were developing symptoms of the dangerous disease — even as they traveled around Boston, the country, and the world.


Concerns about holding large gatherings were already circulating locally at least a week before the Biogen conference. Massachusetts had detected its first coronavirus case on Feb. 1 — a man in his 20s who had flown back from Wuhan, China, where the virus was widespread. On Feb. 19, the Japanese tech company Sony announced that due to concern about infections it would skip the annual PAX East gaming expo at the Boston Convention & Exhibition Center, Feb. 27- March 1.

Biogen spokesman David Caouette said he is unaware of any internal discussions about canceling the Biogen conference due to the global spread of the virus.

“At the time of the meeting, we were absolutely following national guidance on travel and in-person meetings,” Caouette said in a statement.

Guests at the Long Wharf conference included people from Italy, a country where the virus had spread, but not people who had been to China, where it originated late last year, he said.

After a day of highly technical presentations on Wednesday, Feb. 26, many of the Biogen attendees gathered at 6:30 p.m. at the State Room, a few blocks away at 60 State St., for dinner and awards.

The conference picked up Thursday morning and went half a day, concluding in the afternoon, when attendees headed for the airport or home.

By Saturday night, signs of trouble were emerging. One Biogen executive reported feeling sick, and planned to seek treatment at Massachusetts General Hospital in the morning, according to a person familiar with the company. That executive was told on Sunday that a coronavirus test was not warranted under existing criteria, the executive told colleagues on Sunday.


On Monday, another Biogen employee from the conference attended a Naples, Fla., executive round-table, held by the consulting giant PwC. According to Biogen, that employee had flu-like symptoms while at the Florida event. Biogen would not say whether that person has since tested positive ― it declines to discuss individual cases. But PwC said in a statement that it is taking the potential interaction very seriously, informing "all participants who attended our PwC event that one of the participants was in proximity to individuals who have tested positive for COVID-19.”

Biogen chief medical officer Maha Radhakrishnan on Monday sent a message to people who attended the Boston conference advising them to see a doctor if they felt ill.

By Tuesday morning, March 3, more executives who had been at the Boston conference were not feeling well, according to the person with knowledge of the company, who asked not to be identified because of the sensitivity of the situation. Some of them had gone to MGH or to their doctors to request coronavirus testing, only to be rebuffed because they did not meet the federal government criteria for a test, which at the time was a set of symptoms in addition to recent travel to a breakout area or contact with someone known to have the virus.


Biogen officials reached out to public health authorities in Massachusetts on March 3, according to a document obtained by the Globe, to report a cluster of about 50 conference attendees with flu-like symptoms in this region and overseas. Those officials were told that the cases did not satisfy requirements for testing.

Massachusetts Public Health Commissioner Dr. Monica Bharel said in a Tuesday news conference that she is unable to pinpoint exactly when her department learned that people who attended the Biogen conference were ill with Covid-19, and when the agency acted to test others who attended the conference or were in contact with those attendees.

All the days are “blurring together,” Bharel said.

Another person familiar with the events, who asked to remain anonymous because they are not cleared to speak on the issue, confirmed that Biogen’s chief medical officer first contacted the state public health department the morning of March 3. Biogen told DPH that day that a cluster of people who attended the conference were ill, according to the unnamed person.

Biogen called the DPH again the next day, March 4, according to the person familiar with these events, and alerted DPH that at least two people from Europe who were at the conference had tested positive for Covid-19.

That same day, a “significant number" of people from Biogen — though still fewer than 10 — came to the Emergency Department at MGH asking for coronavirus tests, said Dr. Paul Biddinger, chief of the division of emergency preparedness at the hospital.


MGH had not been informed previously of the Biogen meeting or that people had been exposed to the virus.

“There was concern that there may be many more coming,” Biddinger said. Too many Biogen walk-ins, the hospital feared, could disrupt care for other patients.

All the Biogen people got a medical evaluation but many did not have symptoms that would rise to an emergency; they just wanted testing, Biddinger said.

“For each person, we talked to [Department of Public Health] staff about these patients and whether or not they meet testing criteria,” he said. “Some were tested and some were not.”

Some of the Biogen walk-ins became “very frustrated” that they couldn’t get a test. “There were some challenging discussions,” Biddinger said.

At 10 a.m. on March 5, senior Biogen leadership held a call with people who were at the Boston conference, reporting that three attendees had tested positive for Covid-19 outside of Massachusetts.

Several hours later, Biogen executive vice president Alphonse Galdes and Radhakrishnan sent out a message to people across the company describing the illnesses associated with the conference:

“We wanted to inform you that an unexpected high number of attendees have reported varying degrees of flu-like symptoms (fever, headache, cough, body ache, chills, general fatigue, and malaise being among the most common symptoms reported),” the message said. It added that three attendees had tested positive for Covid-19.

The message said the company could not identify the people who had tested positive, but that out of caution, Biogen wanted everyone who was at the conference to work from home.

That information alarmed some employees, who were concerned about having been exposed to the illness in the days prior to the announcement, and were surprised that the company didn’t give employees a better handle on the situation sooner.

Two people familiar with the company said a number of employees got up and left after reading the e-mail, with many of them heading straight to MGH to request a test.

In an e-mail from the company Thursday evening, Biogen officials asked employees to refrain from going to MGH to be tested for the coronavirus. The e-mail said their efforts “are overwhelming the emergency room” and that hospital police may have to bar Biogen employees from entering the area.

Biogen acknowledged for the first time on Thursday night that the coronavirus had been spread at its meeting the week before. By Friday, MGH and Brigham and Women’s set up temporary testing facilities in their ambulance bays to handle an influx of potential patients.

The outbreak at Biogen rippled through the state’s close-knit biopharma industry, which employs about 74,000 people and is marbled with Biogen alumni.

Several of the Biogen executives from the Long Wharf conference also attended a health care event hosted by Cowen and Co. March 2-4, at the Boston Marriott Copley Place, including CEO Michel Vounatsos and other top officials.

Cowen has since warned attendees of its event that Biogen informed Cowen that multiple individuals at the March 2 event have tested positive for Covid-19.

Cowen spokesman Dan Gagnier directed inquiries to Biogen.

Caouette, the Biogen spokesman, said in a statement that the company could not discuss the specifics of the cases, but he confirmed that multiple people from Biogen “who were at the March 2 Cowen investment conference in Boston" have tested positive.

“Several of our colleagues are doing well and others are fighting this novel virus and living in isolation from their families. Knowing they are in pain, hurts each of us,” Vounatsos wrote in an e-mail to staff on Monday.

“I am grateful for the courage our team has shown in this challenging time, working late into the night and in constant communication with public health partners. In particular, I want to thank our medical team for providing their expertise to support our employee’s safety and well-being.”

Edward Fitzpatrick of the Globe staff contributed to this report.