(A) Estimated R0 during the outbreak (mean and 95%CI), as a function of baseline R0 (i.e., that derived by using the contact matrix estimated for the baseline period). The figure refers to Shanghai and the scenario accounting for the estimated susceptibility to infection by age. Three contact patterns are considered: i) as estimated during the COVID-19 outbreak, ii) as estimated during school vacations (7) and iii) as estimated for the baseline period, but suppressing all contacts at school. (B) Daily incidence of new SARS-CoV-2 infections (mean and 95%CI) as estimated by the SIR model assuming age-specific susceptibility to infection (see supplementary materials). Three mixing patterns are considered: i) as estimated for the baseline period, ii) as estimated during school vacations (7) and iii) as estimated for the baseline period, but suppressing all contacts at school. The inset shows the infection attack rate one year after the introduction of the first COVID-19 case (mean and 95%CI). (C) As (A), but assuming equal susceptibility to infection by age. (D) As (B), but assuming equal susceptibility to infection by age.