Washington, Dec 31 (Inditop.com) Under 18-year-olds are more likely than adults to catch swine flu from an infected family member, says a new study.

The data reveals that household contacts aged 18 or under were twice as likely to be infected by a patient in their household compared to adults aged 19 to 50.

No particular symptoms, including cough, runny nose, fever, sore throat, vomiting and diarrhoea, were found more associated with the virus being transmitted between people in the same household than the others.

Scientists from London’s Imperial College and the Centres for Disease Control and Prevention (CDC) in the US analysed data collected by CDC from 216 people infected with the swine flu virus, or Influenza A H1N1, and 600 people living in their households.

They wanted to determine how age, symptoms, number of people in a household and length of time after symptoms are first reported affect how easily people transmit the virus to one another.

Simon Cauchemez of Imperial College, who led the study, said: “If we are advising people to stay at home if they develop flu-like symptoms, we need to understand the implications this might have for other household members.”

“Our new research helps us to do this – for example it shows that children are more at risk of being infected than adults,” said Cauchemez.

The study suggests that it may be unnecessary for patients to stay at home for longer than four days after they start to have symptoms.

It reveals that the average length of time between one person displaying the first symptoms of flu and someone else in their household having symptoms is 2.6 days, said an Imperial College release.

At the start of the current pandemic, CDC advised patients to stay at home for seven days, but it has since revised these guidelines to 24 hours after the end of fever (without the use of fever-reducing medications), which is supported by the new research findings.

The results show that one in eight of the 600 people living with swine flu patients developed symptoms of respiratory illness.

The findings were published in the New England Journal of Medicine.