Children with swine flu are more likely to transmit the virus to other youngsters of the same sex, a study suggests.
Researchers looking into how social interaction contributes to the spread of flu among schoolchildren found that boys and girls were three times more likely to pass it on to children of the same gender.
Being in the same class also increased the rate of transmission five-fold, the study of 370 elementary school pupils from 295 households in Pennsylvania showed.
However, the British and US scientists did not find that sitting next to a child with swine flu increased the chances of being infected.
The researchers used data from seating charts, timetables, bus schedules, nurse logs, attendance records and questionnaires to estimate rates of flu transmission in different settings.
Study leader Dr Simon Cauchemez, from the Medical Research Council’s centre for outbreak analysis and modelling at Imperial College London, said: “This is one of the most comprehensive studies to date on how a flu epidemic spreads between children in school, and it tells us a great deal about how social networks influence transmission.
“The data from this study will help us make more accurate models, which can help public health officials to handle epidemics effectively.
“For example, these new models 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.”