Closing schools could reduce the spread of swine flu by 21 per cent, a new study suggests.

Researchers from a variety of European countries — among them Belgium, England and Wales, Germany and Poland — analyzed previous studies on how close contacts affect the transmission of the flu.

They developed a mathematical model using data about the spread of the flu on holidays and weekends to determine how closing schools would reduce infection. They found that children, who are often in close contact with other kids and don't always wash their hands, are generally exposed to fewer people while at home.

That meant they were less likely to catch and spread flu viruses.

"If we can assume that school closure in a pandemic situation resembles school closure during holiday periods, then our results show that such a strategy would have significant impact on disease transmission of about 21 per cent," they write.

The researchers believe that closing schools can have a "substantial impact on the spread of a newly emerging infectious disease that is transmitted via close (non-sexual) contacts."

The research was published Friday in the journal BMC Infectious Diseases.