NBA Data Reveals New Information About the B.1.1.7 Variant

The viral strain causes a longer period of infection, which could explain its increased transmissibility

Buddy Hield of the Sacramento Kings attempts a three in front of his masked teammates on January 13, 2021. Photo: Ezra Shaw/Getty Images

For this science-writing basketball fan, one of the few good things to come out of the pandemic has been the collaboration between the NBA and epidemiologists. Last summer, the league had the money and motivation to enshrine players, coaches, and staff in a “bubble” for four months — a fascinating premise for any science experiment.

The NBA tested its players and staff every day, at a time when there wasn’t a lot of testing going on in the United States. This setup enabled scientists at Yale University to pilot a new type of diagnostic test that relied on spit instead of a nasal swab. Thanks to the perfectly named SWISH study (Surveillance With Improved Screening and Health), the researchers were able to validate their saliva test for SARS-CoV-2, which was authorized by the U.S. Food and Drug Administration in August.

A new study published this week by scientists at Harvard University built upon this partnership and the daily testing the NBA is now doing for its 2020–2021 season. By conducting genome sequencing on the copious amounts of RNA samples collected, the researchers were able to identify several cases of Covid-19 among players and staff that were caused by the B.1.1.7 variant. First identified in England, the new variant is 50% more transmissible and potentially deadlier than other coronavirus strains. Scientists have several theories as to why the variant behaves differently, but little conclusive data until now.

Of the 65 NBA players and staff members who tested positive for SARS-CoV-2, seven were infected with the B.1.1.7 variant. The scientists compared the course of infection for the strains and discovered that people infected with B.1.1.7 had significantly longer illnesses, lasting for an average of 13.3 days versus 8.2 days for the non-B.1.1.7 virus. What’s more, it took five days for the B.1.1.7 variant to reach peak viral concentration but just two days for the non-B.1.1.7 virus. This means the B.1.1.7 variant is at the most transmissible stage of infection — when the virus is rapidly replicating in the nasal cavity before the immune system kicks in to stop it — for more than twice as long as other strains of the virus. Interestingly, people infected with B.1.1.7 actually had slightly lower viral load in their nose, disproving one of the leading theories for why the variant might be more transmissible.

The authors write, “These data offer evidence that SARS-CoV-2 variant B.1.1.7 may cause longer infections with similar peak viral concentration compared to non-B.1.1.7 SARS-CoV-2, and this extended duration may contribute to B.1.1.7 SARS-CoV-2’s increased transmissibility. The findings are preliminary, as they are based on seven B.1.1.7 cases. However, if borne out by additional data, a longer isolation period than the currently recommended 10 days after symptom onset may be needed to effectively interrupt secondary infections by this variant.”



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Dana G Smith

Dana G Smith

Health and science writer • PhD in 🧠 • Words in Scientific American, STAT, The Atlantic, The Guardian • Award-winning Covid-19 coverage for Elemental