What we think is most likely is that 3- and 4-year-olds are early spreaders of influenza because of the preschool setting.
What this is really showing us is that there potentially is a discretionary part to emergency room visits. We're not talking about gunshot wounds or car accidents but at the level of a really bad cold.
As the game gets more serious or more important, the effect gets stronger in a linear fashion. We didn't see any spikes after the games in visits. What we assume is that people decided to wait.
They exposed their vulnerable grandparents to the flu.
It wasn't like people were holding off until the ninth inning and then running to the emergency department.
Close quarters, poor hygiene. It just makes for a hotbed of infection in day-care centers. Preschool kids have a high level of (flu) transmission, and they bring it home.