| |
Covid-19 / Up to 300,000 Cases
Are Traced to Feb. Boston Biotech Conference
|
| |
| |
Download the PDF here
Superspreading Boston biotech conference in February is linked to 1.9 percent of all U.S. cases.
https://www.nytimes.com/live/2020/12/12/world/covid-19-coronavirus#superspreading-boston-biotech-conference-in-february-is-linked-to-1-9-percent-of-all-us-cases
Convened by Biogen in February, it was one of the earliest examples in the pandemic of what epidemiologists call a superspreading event. The F.D.A authorized Pfizer’s vaccine for emergency use on Friday, clearing the way for millions of people to begin receiving the vaccine within days.
By March, the researchers had found, viruses bearing the same signature began to appear in the viral genomes taken from coronavirus patients in several other states. But by November, viruses containing the marker could be found in 29 states, linked to some 70,000 in Florida alone. And because the viral genome data linked to U.S. cases has grown by tenfold since June, the researchers are able to make a reliable national estimate. The conference, the study estimates, is responsible for 1.9 percent of all cases in the United States since the start of the pandemic.
A vast majority of introductions of the virus into a workplace or home or community fizzle, the researchers noted. But the study highlights how a local event with a mobile population can seed a national outbreak. Because the genetic fingerprint identified in the Biogen attendees existed previously in Europe, it was not possible to reliably estimate how many of the transmissions globally came from the Boston event, the researchers said.
Although the Biogen conference occurred at a time when the coronavirus was barely on the radar for most Americans, it might have important implications for the current pandemic moment. The first, eagerly awaited vaccines have been demonstrated to protect from severe Covid-19 symptoms, but it is not known whether they protect people from transmitting the virus.
------------------------------
Phylogenetic analysis of SARS-CoV-2 in Boston highlights the impact of superspreading events
Science 10 Dec 2020 pdf attached
Genome data reveal that the impact of the conference was far larger than the approximately 100 cases directly associated with the event. Using state-reported case counts, we estimate that by the end of the study period, approximately 50,000 diagnosed cases [44,000 - 56,000] in the US resulted from conference-associated viruses; of these, 46% [40.4 - 51.8%] were in Massachusetts. Through November 1, 2020, we estimate that a total of 245,000 [205,000 - 300,000] cases marked by C2416T, and 88,000 [56,000 - 139,000] cases marked by G26233T, were linked to the conference in the United States. While Massachusetts accounted for most early spread related to the conference, Florida accounted for the greatest proportion of cases overall (29.2% [22.8 - 36.0%], S15G).
Abstract
Analysis of 772 complete SARS-CoV-2 genomes from early in the Boston area epidemic revealed numerous introductions of the virus, a small number of which led to most cases. The data revealed two superspreading events. One, in a skilled nursing facility, led to rapid transmission and significant mortality in this vulnerable population but little broader spread, while other introductions into the facility had little effect. The second, at an international business conference, produced sustained community transmission and was exported, resulting in extensive regional, national, and international spread. The two events also differed significantly in the genetic variation they generated, suggesting varying transmission dynamics in superspreading events. Our results show how genomic epidemiology can help understand the link between individual clusters and wider community spread.
|
|
| |
| |
|
|
|
