In a paper, published in the British journal The Lancet Infectious Diseases, the researchers said: 'Notably, the rate of infection in children younger than 10 years (7.4 per cent) was similar to the population average (6.6 per cent).
There was no significant association between the probability of infection and age of the index case.'
This meant that children were as likely as adults to both catch the virus and to spread it.
The researchers added: 'Analyses of how cases are detected, and use of data on individuals exposed but not infected, indicate that infection rates in young children are not lower than the population average (even if rates of clinical disease are).'