SCOTT SIMON, HOST:
Millions of football fans without masks have been going to games, cheering for their pro, college, high school teams. Now, at the start of the season, many epidemiologists strongly advised against this. They worried that games could become superspreaders. But so far, as NPR's Wade Goodwyn reports, that just hasn't happened.
WADE GOODWYN, BYLINE: Given how contagious the delta variant of the coronavirus is, packed football stadiums with the vast majority of the fans not wearing masks, standing right next to each other while yelling their hearts out for hour after hour seems like a suboptimal idea.
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UNIDENTIFIED ANNOUNCER: Thompson to pass, quick to Worthy. He's got the first down. Still up, Worthy, inside the 20 to the 10. And on fourth down, Xavier Worthy makes the play.
GOODWYN: At Darrell Royal-Texas Memorial Stadium in Austin, a sea of humanity cheers for the Longhorns, nearly all of them unmasked.
BILL HAEHNEL: Everybody is shoulder to shoulder going into the stadium, sitting in the stadium, coming out of the stadium.
GOODWYN: Bill Haehnel is a UT alumnus, a former member of the Longhorn Band back in the late '70s, who now has season tickets. He also helps out in the UT Alumni Center before the game begins. Like others working there, Haehnel is vaccinated and wears a mask. But he estimates roughly 9 out of 10 of the alumni who pack the place during the 90 minutes before kickoff don't wear masks.
HAEHNEL: Bottom line is I think people aren't living in fear anymore. They just don't want to be living in fear anymore. And that's a choice I've made.
GOODWYN: Just like Bill Haehnel, nearly all the fans in attendance sit unmasked in their seats. So that raises the question, infection-wise, is it OK for a packed crowd to be unmasked and yelling vigorously for the duration of the game? In the weeks before this season began, many epidemiologists around the country strongly discouraged this. It's about the risk of upper respiratory tract infection, which can be spread from fans who are not aware they're infected to the uninfected fans seated right next to or in front of them.
ADRIAAN BAX: You got to think of it like smoke.
GOODWYN: Adriaan Bax is a biophysicist at the National Institutes of Health. He says imagine cigarette smokers lighting up inside a packed room. Though large, the spaces eventually fill to some degree with exhaled smoke hanging in the air. Bax says these circumstances present a meaningful risk of infection.
Now let's go to the football stadium, where there's a modicum of blowing wind. Here, the smoke, our metaphor for the coronavirus, is thinned by the amount of moving air, its dispersal not restricted by walls and a roof. NIH scientist Adriaan Bax again.
BAX: Outside, the risk is much lower. So even with the delta variant being so infectious, inside the stadium, it's probably not so bad.
GOODWYN: Unfortunately, not so bad in America is not all that great. Every day, more than a thousand Americans die due to the coronavirus. That's every day. It's mostly a reflection of how many Americans remain unvaccinated. But in an effort to track the virus at various universities around the country, they're monitoring dorm room sewage for evidence of the coronavirus. Cindy Prins is a professor of epidemiology at the University of Florida, where they're doing just that.
CINDY PRINS: We have gator watch, so that's been a consistent part of our pandemic response is to look for cases of COVID-19 by identifying the virus in sewage.
GOODWYN: When it comes to judging the relative risk of infection to students at games, this is hardly an exact science. There are plenty of dorm students who don't go to football games. Nevertheless, there's a significant number of enthusiastic freshmen and sophomores who do. Here's Professor Prins again.
PRINS: We're not really seeing any links between these events and the number of places or level of positives we're getting with wastewater testing. And we're not seeing an increase in cases.
GOODWYN: John Brooks, a senior science adviser at the Centers for Disease Control and Prevention, agrees.
JOHN BROOKS: For people who are fully vaccinated and then in that outdoor environment, so far, there hasn't been a real signal that this is a serious risk for transmission.
GOODWYN: Remember National Institutes of Health scientist Adriaan Bax? At the end of our interview, I asked him if I gave him two free tickets to a college football game packed with 80,000 people, would he go?
BAX: I would say great, but I'd be showing up with an N95 mask and sitting there with my wife with an N95 mask and avoid any kind of indoor beer drinking or other kind of festivities. It's perfectly safe if you're outside, even in a stadium, as long as you wear a mask.
GOODWYN: But mostly, that's not happening. Without a mask, your odds of not getting infected at the stadium are probably OK - no guarantees, though - but NIH scientist Adriaan Bax and his N95-masked wife sitting over there in section 26 are definitely going to have you whipped.
Wade Goodwyn, NPR News, Dallas. Transcript provided by NPR, Copyright NPR.