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Weekly reported cases of VPD from NNDRS.We estimated the baseline weekly average incidences of the relevant VPDs from 2017 to 2019, and assessed the differences between those baseline values and the weekly incidences of the same VPDs in 2020. Meanwhile, we chose Chinese New Year in 2017–2019 as the key time point (11 weeks before and 39 weeks after the key time point).
