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. 2021 Jul 13;36:100483. doi: 10.1016/j.epidem.2021.100483

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© 2021 The Authors

Since January 2020 Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre - including this research content - immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

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Fig. 2 — Epidemic curve of the COVID-19 outbreak in Zhejiang and model fitting results. (A) Fitted sigmoid function of social contact change. Zhejiang changed its infectious disease alert category to the highest level on January 23rd, 2020 (left red vertical line) and started a comprehensive set of restrictions on February 1st, 2020 (right red vertical line). (B) The distribution of isolation speed (days). (C) The distribution of contact tracing proportion. (D) Model fitting curve and observed counts of confirmed symptomatic cases by their symptom onset date.