Researchers say the Biogen conference likely caused 20,000 COVID-19 cases in the Boston area

of Survey on page 64 The paper has not been peer-reviewed yet, and the researchers’ estimates-not shown in the paper but shared in the interview-are estimates based on viruses isolated from 772 local patients. Stressed. But they believe their calculations are sound.

Dr. Jacob Lemieux, an infectious disease doctor at the Massachusetts General Hospital and one of three scientists at the Broad Institute at MIT and Harvard University, said: A study they wrote with 50 other researchers.

Caroline Bucky, a professor of epidemiology at Harvard TH Chan School of Public Health who was not involved in the study, believes the 20,000 estimates associated with the conference, assuming the coronavirus analyzed by the researchers is a representative sample. There was no problem with the case.

“Super-diffusion is really an important factor in the way we ended up with this epidemic of gravity,” said Buckee, who received a copy of the study before it appeared Tuesday on pre-print servers. “Considering, every case in the world came from a single case. That is the nature of the exponential increase in epidemics.”

The team analyzed the gene sequences of the virus that caused COVID-19 in 772 patients. Almost all are patients in the counties of Essex, Middlesex, Norfolk, and Suffolk. A subtle change that acts like a passport stamp of where the pathogen was by looking for mutations in the genetic code that naturally occur when the virus makes a copy of itself — detectives over 80 infected Identifying the SARS-CoV-2 Genome of the Virus Boston Area for the First Five Months of the Year. According to scientists, most of the viruses came from elsewhere in the United States and Western Europe.

However, one virus with a unique genetic signature had an oversized effect. About 289, or more than 3, of the 772 patients were infected with traceable virus at a meeting held by Cambridge Biotechnology Biogen on February 26-27.

The study found 289 conference-related incidents in the Boston area as a notable sign of how the virus spread unexpectedly and disproportionately to the most vulnerable members of society. It included 122 people and employees living in homeless shelters. The route by which the virus reaches it is unknown.

Scientists multiply the percentage of conference-related viral genomes in each of the four counties by the total number of Essex, Middlesex, Norfolk, and Suffolk coronavirus infections, with 20,000 infections associated with the Marriott event. I presume.

Biogen is not mentioned by name in this study. It simply means “International Business Conference in Boston from February 26th to 27th”.

“We’re not trying to point our fingers,” said Bronwyn MacInnis, one of Broad’s directors of pathogen surveillance and interviewed. “A few [viral] The introduction is blown away, and others have a light fire. The context of this event, the fact that it happened very early in the epidemic, and the timing when we put COVID into public awareness meant that it had a disproportionate effect. .. It happened in a city that wasn’t “awake”. “

In response to the, Biogen said the outbreak at the conference occurred almost six months before there was limited understanding of COVID-19. However, the company did not object to this investigation or the presumption of 20,000 conference-related cases.

“We wouldn’t have intentionally put anyone at risk,” he said in a statement. “When I learned that many colleagues were ill, I didn’t know that the cause was COVID-19, but I immediately notified public health officials and took steps to limit the spread. “

In April, the company joined a group that included Broad, Brigham, Women’s Hospital, and Mass General, who created a collection of biological and medical data about viruses.

“In today’s world, there is a deeper understanding of how easy and fast this virus can spread. We are proud to have contributed to the global effort to overcome COVID-19 through this collaboration. Yes,” Biogen said.

This study was a collaborative study of researchers from several institutions, including Broad, Massachusetts General, and the Massachusetts Public Health Department. As a separate effort, the Department of Health used contact tracking to tabulate at least 99 coronavirus cases resulting from the meeting before the staff stopped counting Biogen-related infections in late March.

In addition to Lemieux and MacInnis, Broad’s senior computational biologist Stephen Schaffner, who worked on the study, talked to Globe about the findings.

The researchers sequenced the genome of the SARS-CoV-2 virus isolated from 772 patients in Greater Boston — as much as scientists have available — most often from March 4th to May 9th Until. Homeless programs and other medical facilities.

More than 80 different coronavirus genomes identified by researchers also included those apparently arrived in late January when travelers returned from Wuhan, China, the epicenter of the then pandemic. The patient was isolated in Massachusetts, and researchers found no evidence that the patient had infected anyone.

However, the first big event gathering in Massachusetts seems to have come from Biogen’s gathering of about 175 corporate leaders from the United States and abroad.

About 37% of the 772 genomes sequenced by the researchers had the same genetic characteristics. They included sequences of viruses isolated from 28 people known to have attended meetings, worked at hotels, or had direct contact with those individuals. Twenty-eight of them provided viral samples when they sought medical attention immediately after the meeting, many of which were MGH.

According to scientists, the Marriott gatherings were a perfect storm for super-proliferation. The event was attended by participants from a distance. They packed up in hotel elevators and escalators, sat close to each other at meetings, and socialized over food and drink. This conference took place before many Americans took precautionary measures against COVID-19.

“Because it happened early in the epidemic, it had the opportunity to spread widely before widespread competence, closure, social distance, and masking took place,” three scientists said in an email.

Patients with conference-related viral genomes included 122 who lived in or worked with homeless shelters in Greater Boston. Many have called for treatment through homeless healthcare programs. No refuge was identified in this survey.

The three authors said they had no idea how the virus spread from the conference to homeless shelters. “But it shows that we’re all connected and the more vulnerable population is overly affected by COVID-19. Once in the homeless community, it’s ready to spread widespread. “They said in an email.

Scientists emphasized that the 20,000 estimates associated with meetings in the four counties were “calculations against the envelope.” The total number of people infected with the virus spread from the conference could be much higher because the researchers did not look at cases outside the four counties, or in other parts of the country or abroad. The outbreak at the conference is believed to have triggered a series of incidents in Tennessee, North Carolina, Indiana, New Jersey, Washington DC, and abroad.

“An accurate estimate of the total number involved [globally] “It’s not possible with current data, and maybe not at all,” said the scientists. “If tens of thousands of individuals appear to be large, [the] The situation of a pandemic that has infected tens of millions. “

The three scientists provided some warnings. They suspect that the viral genomes from patients seeking care from Mass General and other health care providers may not be representative of the county coronavirus that the researchers used to extrapolate them. They said.

Also, a version of the virus that is believed to bounce back at the conference was infected undetected from another local super-spreader event, infecting people at Marriott, confusing researchers about its true origin. There is also a possibility. But scientists said in their email, “I don’t see any evidence of that.”

Dan Hartle, a biology professor at Harvard University who specializes in population genetics and is not involved in research, said the estimates for 20,000 cases are reliable. He added that there was probably nothing special that led to the spread of conference-related viruses.

“Oh, well, this one virus seems to be much more widespread than the others. Is there anything special?” he said. “Not necessarily. I got lucky and spread to one of these super spreader events.”

Jonathan Salzman [email protected]