Reconstructing a Pandemic

Researchers estimate that a biotech conference in February led to hundreds of thousands of infections. What can that teach us about the spread of COVID-19?

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Last Friday morning, I received a phone alert from the Boston Globe: epidemiologists and genomicists had traced covid-19 infections at a Boston biotech conference in late February and estimated that, by October, the conference had led to between some two and three hundred thousand cases, across twenty-nine states and multiple countries. That was the headline, but the substance of the paper, which appeared in Science, was a careful tracking of a mutation of the coronavirus that had appeared among patients who were infected at the conference, which was held by the drug company Biogen, and then moved through Massachusetts and to other states and continents. These are the kind of empirical facts that have been in short supply, and they provide a glimpse of not just a cluster of infections isolated in place and time but a branch of the pandemic as it spread through the world and through the year.

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By 4 p.m. Friday, I was on a video call with the two lead authors of the paper, Jacob Lemieux, an infectious-disease physician and postdoctoral researcher at Harvard, and Bronwyn MacInnis, the director of pathogen genomic surveillance at the Broad Institute’s Infectious Disease and Microbiome Program. They looked a little worn out, having spent the day trying to explain a paper about the processes of superspreading to reporters who were primarily interested in how many infections could be traced to the conference. “In the initial version of the paper, we didn’t have a number—we didn’t want to go there,” Lemieux said. “People kept asking, ‘How many cases? How many cases?’ So we did our best, as scientists, to flesh this out.” Lemieux noted that, though the paper offered an estimate of the number of infections, it also included half a paragraph of caveats, most of which acknowledged the incompleteness of databases of coronavirus genomes and the imperfections of the calculations,

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