Common sense dictates that bringing together 25,000 people during a pandemic could lead to more coronavirus infections, and the Super Bowl in Tampa, Fla., is no exception. But trying to pin down how many infections could stem from this event has frustrated scientists because contact tracing is often spotty, even more so when fans after Sunday’s game return to their homes in all corners of the country.Donald Burke, an epidemiologist who teaches at the University of Pittsburgh, is trying to develop a way to estimate the potential spread of the virus using cellphone tracking data, statistics on the transmission of viruses and other information. He hopes that models created by his company, Epistemix, can be used by public health officials and event operators to decide if it is safe enough to host large gatherings, including football games with fans.“The question is, what is the impact of a given event,” Burke said. “Every institution is trying to figure out what’s the relative effect.”The models, however, only track people attending a specific event, not the many other events that happen nearby. The N.F.L. may impose restrictions on behavior in its facilities, but events like the Super Bowl attract tens of thousands of other people, as has happened in Tampa, where there have been reports of large gatherings of people without masks.And while fans might wear masks inside stadiums, they often tailgate or visit pubs and restaurants before and after games. In November, health officials in Texas said that eight residents who tested positive told contact tracers that they had recently attended Dallas Cowboys home games. It is unclear whether they were infected before, during or after the games.There will be about 25,000 fans at the Super Bowl, but 7,500 of them will vaccinated health care workers. Other fans will sit in small groups separated from others. The league is not requiring that fans be tested or vaccinated before entering the stadium, but some fans may have received one or both. The N.F.L. is giving every fan a KN95 mask and hand sanitizer, and fans must wear masks except when eating or drinking.One variable will be the choices of fans after the game. Some may get tested when they get home or proactively self-quarantine to avoid potentially infecting others. Others may wait to see if they begin feeling symptoms, by which point they will have likely been transmitting the virus for day.“Modeling the virus is the easy part,” Burke said. “Modeling the humans is the hard part.”He doesn’t think the N.F.L. should be too worried about widespread infections from the game because it has taken measures to protect fans. But Burke’s models could be improved with data on where fans come from, what portion wear masks and other information.“This is the kind of science that we should be doing,” he said.