20 BACKGROUND The COVID-19 epidemic, first emerged in Wuhan during December 2019, has 21 spread globally. While the mass population movement for Chinese New Year has significantly 22 influenced spreading the disease, little direct evidence exists about the relevance to epidemic and its 23 control of population movement from Wuhan, local emergency response, and medical resources in 24 China. fatality rate was 2.84%, much higher in Hubei than in other regions (3.27% vs 0.73%). The index of 29 population inflow from Hubei was positively correlated with total (Provincial r=0.9159, p<0.001; 30 City r=0.6311, p<0.001) and primary cases (Provincial r=0.8702, p<0.001; City r=0.6358, p<0.001). 31 The local health emergency measures (eg, city lockdown and traffic control) were associated with 32 reduced infections nationwide. Moreover, the number of public health employees per capita was 33 inversely correlated with total cases (r=-0.6295, p <0.001) and infection rates (r =-0.4912, p <0.01). 34 Similarly, cities with less medical resources had higher fatality (r =-0.4791, p<0.01) and lower cure 35 rates (r = 0.5286, p<0.01) among the confirmed cases. 36 CONCLUSIONS The spread of the COVID-19 in China in its early phase was attributed primarily 37 to population movement from Hubei, and effective governmental health emergency measures and 38 adequate medical resources played important roles in subsequent control of epidemic and improved 39 prognosis of affected individuals.40 41 .CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.(which was not peer-reviewed) The copyright holder for this preprint .

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Fast and accurate detection of microbial cells in clinical samples is highly valuable but remains a challenge. Here, a simple, culture‐free diagnostic system is developed for direct detection of pathogenic bacteria in water, urine, and serum samples using an optical colorimetric biosensor. It consists of printed nanoarrays chemically conjugated with specific antibodies that exhibits distinct color changes after capturing target pathogens. By utilizing the internal capillarity inside an evaporating droplet, target preconcentration is achieved within a few minutes to enable rapid identification and more efficient detection of bacterial pathogens. More importantly, the scattering signals of bacteria are significantly amplified by the nanoarrays due to strong near‐field localization, which supports a visualizable analysis of the growth, reproduction, and cell activity of bacteria at the single‐cell level. Finally, in addition to high selectivity, this nanoarray‐based biosensor is also capable of accurate quantification and continuous monitoring of bacterial load on food over a broad linear range, with a detection limit of 10 CFU mL−1. This work provides an accessible and user‐friendly tool for point‐of‐care testing of pathogens in many clinical and environmental applications, and possibly enables a breakthrough in early prevention and treatment.