Flu in kids typically spreads boy to boy and girl to girl

By Shari Roan, Los Angeles Times

Jan. 31, 2011 12 AM PT

Flu spreads faster in schools than rumors about a pop quiz. But science is revealing more about how germs jump from child to child and strategies that might prevent larger flu outbreaks.

The latest science shows that flu predominantly spreads from boys to other boys and from girls to other girls. The study, conducted by a consortium of researchers that included experts from the U.S. Centers for Disease Control and Prevention, also found that flu transmission is more intensive within students sitting in the same class. But sitting next to someone with the flu doesn’t, in itself, increase one’s risk.

The scientists examined flu spread among 370 children, ages 6 to 18, during a major H1N1 flu outbreak in a rural Pennsylvania community. The goal was to look at how social networks control flu spread.

Children are about three times more likely to pass the flu to children of the same gender, the researchers found. That’s probably because boys tend to mix with boys and girls with girls. Transmission rates were five times higher between classmates compared with children in a different class but in the same grade. Children ages 6 to 10 had the highest infection rate, followed by children age 5 and younger.

Tracking just how flu spreads, “could help us better understand whether and when it would be appropriate to close a school, or whether it might be better to close individual classes or grades,” Dr. Simon Cauchemez, the lead author of the study and a researcher at Imperial College London, said in a news release. School closings are considered useful for controlling the spread of flu during a pandemic but create a fair amount of inconvenience and upheaval for school officials and families.

The study was published Monday in the Proceedings of the National Academy of Sciences.

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