London - If someone in your house has flu, you have a one in three risk of developing it and the symptoms will occur, on average, just 56 hours later.
Researchers for the World Health Organisation (WHO) also found that the more children there are in the house, and the younger they are, the more likely it is that others in the house will catch it.
Worldwide data on flu was analysed at the World Health Organisation Collaborating Centre for Infectious Disease Epidemiology and Control at the University of Hong Kong, which concluded that the risk can be reduced by improving ventilation and taking antiviral drugs as a preventative measure.
Daily Mail