A new study that links having a local team in the Super Bowl to an increase in influenza deaths may have some fans in New England and Seattle making last-minute adjustments to their game day plans on Sunday.

Using county-level vital statistics data from 1974-2009, researchers at Tulane University found that having a local team play in the big game causes an 18 percent increase in influenza deaths for people over the age of 65. Researchers say an increase in local socialization is likely behind the link.

The researchers determined control groups and test subjects based on a team’s success in the playoffs, and a subsequent shift in social behaviors in the correlating hometown. A city without a team in the playoffs was deemed the control group. A team’s success correlated with an increased social mixing with the local population, whether through private gatherings or watching the game at a bar.

The study noted that while people age 65 or older may not change their social behavior due to a team’s success, their chances of coming into contact with someone who has increases, making them more likely to get influenza.

“Effects are most pronounced in years when the dominant influenza strain is more virulent, or when the Super Bowl occurs closer to the peak of influenza season,” the study authors said in a paper.

In addition to a shift in socializing patterns, the study authors noted two other mechanisms through which a local team’s success could impact influenza transmission. Citing postseason play, authors noted fan mobility, which leads to “increasing opportunities for exchange as well as co-infection.” The authors also noted that “postseason play may affect local economies in areas with participating teams, through increased tourism from outside or increased local expenditures.”  

Researchers said their paper didn’t suggest that vulnerable populations completely avoid Super Bowl festivities, but they did note that these people could wash their hands, and avoid sharing food and drink to minimize their risk.

“Mitigating influenza transmission at gatherings related to large spectator events could have substantial returns for public health,” the authors said.