On the other hand, experience in Japan confirmed the conclusions from modelling [30] . Early widespread school closures in a defined area were successful in delaying pandemic spread in that area, but when the schools were re-opened, pandemic spread resumed [35] . In Hong Kong closure of kindergartens, pre-schools and primary schools appeared to decrease the attack rate in children aged less than 12 years for the weeks of closure [36] but the effect on the final attack rate in school children is yet to be evaluated. Indeed, it has been argued that the potential benefit of closing schools during a pandemic must be balanced against the enormous social disruption that ensues [37] . Only where schools were closed early and remained closed would there have been any significant interruption of the spread of the pandemic.