This event, a biotechnology conference attended by 200 people at the end of February, is now well known as a source of the spread of Covid-19 very early in the pandemic.
“Ultimately, over 90 cases were diagnosed in people associated with this conference or their contacts, which raised suspicions that a large-scale event occurred there,” the researchers wrote in their study.
Overgrowth occurs when one or a few infected people cause a cascade of transmissions of an infectious disease.
The new study – which has not yet been peer reviewed but was published Tuesday on the online server medrxiv.org – consisted of analyzing the impact of the first mass-market events in the Boston area and provided “direct evidence” that over-diffusion can profoundly alter the course of an epidemic.
‘A perfect unhappy storm’
The researchers – from the Broad Institute of MIT and Harvard in Cambridge and other various institutions – performed genetic analyzes of samples of coronavirus specimens in Massachusetts.
The researchers sequenced and analyzed 772 complete genomes of the virus in the region. They found 80 introductions of the virus in Boston, mostly elsewhere in the United States and Europe, and “hundreds of cases of major epidemics” in various settings, including the conference.
The conference, which was held Feb.26-27, was a “perfect storm” and the super-spread could have been linked to around 20,000 cases, Bronwyn MacInnis, a researcher at the Broad Institute who worked on the study, in an email on Tuesday.
“There are many factors that made the conference a perfect unfortunate storm as a mass-market event. The fact that the virus was introduced at the conference was not at all lucky, ”MacInnis wrote in the email.
“This is not a hard estimate, but communicates the scale,” MacInnis added.
“If tens of thousands of people look great, it is important to stress that it is in the context of a pandemic that has infected tens of millions of people.”
The timing was crucial. At the end of February, people were not yet aware of the risk of a pandemic.
“When it happened was critical: it was planned just as we collectively began to appreciate the looming threat of COVID at home – if it had been a week later, the event would likely have been canceled,” he said. MacInnis wrote in the email.
“Plus, because it happened at the start of the epidemic, it was fortunate enough to spread widely before extensive testing capabilities, closures, social distancing and masking were in place,” she wrote.
“The other critical factor was the population the virus landed in: people who came from many different places (including some where COVID was already circulating), and who then returned home, often bringing the virus without their knowledge. . “
“A much better understanding of the ease and speed with which this virus can be transmitted”
Although the researchers did not identify the conference in their study, the Boston Globe said on Tuesday that it was an international meeting of executives from biotech company Biogen at the Marriott Long Wharf hotel in Boston.
“February 2020 was almost a year and a half ago and was a time when general knowledge about the coronavirus was limited,” Biogen said in a written statement to CNN on Tuesday.
“We closely followed the official guidelines in force. We would never knowingly put people in danger. When we learned that a number of our colleagues were sick, we weren’t sure the cause was COVID-19, but we immediately informed public health authorities. and took steps to limit the spread. ”
The company noted in its statement that it joined a collaboration with the Broad Institute in April to share biological and medical data to advance knowledge about Covid-19.
“The world today has a much better understanding of the ease and speed of transmission of this virus, and we are proud to contribute through this collaboration to the global effort to defeat COVID-19,” said he declared.
Massachusetts Gov. Charlie Baker told a press conference on Tuesday that he viewed the Biogen conference in February as a “milestone” in the Boston-area coronavirus pandemic.
“I was actually criticized for saying a few months ago that the Biogen event was a crowning event here in the Commonwealth and I couldn’t put a number on that at the time- there, ”Baker said.
“It’s not an offense to anyone, but at that time, no one was wearing a mask, no one was social distancing, no one was even behaving with concern about the presence of the virus. I mean all the rules of the game regarding that have changed, ”Baker said. “It is a testament to the power of this virus to pass from one person to another. ”
The new pre-printed study also investigated the spread of the coronavirus in other Boston area settings, including a skilled nursing facility – where 85% of residents and 37% of staff have tested positive – and a homeless shelter – where the coronavirus has been introduced seven times, including four that have resulted in clusters of cases, according to the study.
“Our results repeatedly underscore the close relationships between seemingly disconnected groups and populations: Viruses from international business travel have caused major epidemics among homeless people, have spread throughout the Boston area, and have been exported to other national and international sites, ”the researchers wrote in the study.