A preliminary study submitted to The Lancet scientific journal links fan attendance at NFL games last season to spikes in COVID-19 cases in host counties.
Meanwhile the NFL promoted an MIT study that found no “case clusters” in the aftermath of 119 games played in front of fans last season.
Study: 'NFL games led to episodic spikes'
The independent study linking fan attendance to COVID-19 spikes was co-authored by researchers from the University of Southern Mississippi, the University of Miami, Georgetown and Texas A&M. It studied the aftermath of 269 games last season — 117 with fans and 152 without fans as a control group. The study found that "the evidence overwhelmingly supports that fan attendance at NFL games led to episodic spikes in the count of COVID-19 cases/rates" without concluding a causal link.
The results of the study are preliminary and have not yet been peer-reviewed.
Per the study, games with fan attendance of less than 5,000 were not linked to spikes in COVID-19 while games with 20,000-plus fans "generated significantly greater spikes in the case count":
"The results of this primary analysis of COVID-19 incidence levels in the context of mass gatherings at sporting events provides compelling evidence that the presence of fans at NFL home games during the 2020/2021 season led to increased levels of COVID-19 cases and rates both in the counties in which the venues are nested within, and the surrounding counties in which fans likely travel from to attend.
"The increased spikes in COVID-19 cases and rates among those games attended by fans, particularly for large crowds of over 20,000 suggest that return to sporting and other mass gathering events should be handled with extreme caution and may indeed be premature."
The study was published on March 30, the same day NFL commissioner Roger Goodell announced the league expects to have full stadiums next season.
Nineteen teams hosted fans at varying capacities last season while 13 stadiums remained empty. The Dallas Cowboys led the league in attendance with an average of 28,187 fans per home game, per ESPN. The Jacksonville Jaguars (15,919) and Tampa Bay Buccaneers (14,483) ranked second and third in average attendance.
NFL: MIT study didn't find a link
In an interview with the New York Times, NFL executive vice president for communications Jeff Miller cited MIT Sports Lab research that found no notable increases in COVID-19 infection rates “in the appreciable time frame following the games.” He described the data as "heartening."
The MIT study Miller cited is unpublished, according to the Times.
Proving causation a significant research challenge
The Times also spoke with a CUNY expert who emphasized the difficulties of drawing causation conclusions either way in linking fan attendance to COVID-19 spikes. Bruce Y. Lee, the executive director of Public Health Informatics Computational and Operations Research at City University of New York School of Public Health, pointed out that NFL games generate gatherings away from stadiums as friends and family watch together in bars and homes.
“The strength of these studies is they are showing something, but the correlations can only point out the possibilities, not the causation,” Lee said. “It’s not just a football game and people go home. There are all these associated activities around the game.”
Lee's analysis suggests that studies would need to use detailed contact tracing data that's scattered and not widely available to reach a precise conclusion on the impact of NFL fan attendance on the spread of COVID-19.
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