Another factor is how and when people interact with one another, which is what this study explores well, Janies said.
"Transmission depends on close contact so that respiratory droplets can go from person to person. In a school, or in an airplane, people are closer than they would be in a normal environment," Janies said. "Instead of assuming how people interact, they measured it in the real world."
Typically, computer simulations about the spread of disease rely on lots of assumptions about social interactions, sometimes gleaned through U.S. Census data or traffic statistics, according to background information in the article.
Few researchers have looked specifically at how people interact in a location where there is lots of close contact, such as a school, Salathe said.
"Simply asking people how many people they talked to in a given day doesn't work," Salathe said. "You can have hundreds of really short interactions throughout the day and there is no way to recall all of them."
In the study, 788 students, teachers and staff, which included 94 percent of the school population that day, wore a matchbook-sized wireless sensor on a lanyard around their necks. The device sent out a signal every 20 seconds that could detect if someone in close proximity was also wearing a sensor.
Though there are ethical implications, it's possible that in cases of vaccination shortage, it might make sense to give vaccination priority to those with large contact networks, Salathe said.
The U.S. Centers for Disease Control and Prevention has more on the transmission of infectious diseases.
SOURCES: Marcel Salathe, Ph.D., assistant professor of biology, Pennsylvania State University, University Park;
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