It is generally accepted that children, especially children of school age, are responsible for amplification of influenza epidemics [28] . An intervention targeting schools could therefore theoretically be effective in interrupting an epidemic. This assumption is supported by modelling studies, but only when all schools are closed early and remain closed for an unrealistically long period, up to the duration of the pandemic [29] . Modelling also shows that delay in closing schools, or partial closure of schools, are less effective interventions, [29] although, if school closures are timely, they may delay the peak and decrease the peak incidence of the epidemic [30] .