A timely understanding of the spatiotemporal pattern and development trend of COVID-19 in the early stage of the epidemic is highly significant for epidemic prevention and control early in the epidemic. Therefore, many scholars use reported cases to explore spatiotemporal characteristics of COVID-19 early in the epidemic. However, under-reporting is commonly prevalent and may produce incorrect inferences . In this paper, confirmed cases of healthcare workers were used to analyze the impact of under-reporting on the spatiotemporal distribution of COVID-19  . The results show that: (1) the  estimated peak infection time of the reported cases lags behind the actual peak infection time . The infection peak time of the epidemic in Wuhan was January 29, not February 11 estimated by reported cases, and the infection peak time of the epidemic in Hubei (except Wuhan) was February 2, not February 4 estimated by reported cases. (2) The estimated infection time interval of the reported cases is smaller than the actual interval. The infection time interval of the epidemic in Wuhan was approximately 63.6 days, not 45.6 days estimated by reported cases, and the infection time interval of the epidemic in Hubei (except Wuhan) was about 58.8 days, not 40.8 days estimated by reported cases. ( 3  ) Although the number of reported cases is lower than the actual number of cases, a high spatial correlation exists between the cumulatively reported cases and the actual situation. This work provides scientific support for researchers that explore the spatiotemporal distribution of COVID-19 using the data on reported cases.
A timely understanding of the spatiotemporal pattern and development trend in the early stages of the of COVID-19 epidemic is highly significant for timely prevention and control . However, under-reporting is commonly prevalent in the early stages of an epidemic . In this paper, confirmed cases of healthcare workers are considered as accurately small samples to analyze the impact of under-reporting on the spatiotemporal distribution of COVID-19 from three perspectives, namely: parameter estimation, spatiotemporal correlation, and spatiotemporal lag . The results show that: (1) the lognormal distribution was the most suitable to describe the evolution of epidemic with time. (2) The estimated peak infection time of the reported cases lags behind the peak infection time of the healthcare worker cases, and the estimated infection time interval of the reported cases is smaller than the infection time interval of the healthcare worker cases. ( 3 ) The impact of under-reporting cases on the early stages of the pandemic is greater than that on its later stages, and the impact on the early onset area is greater than that on the late onset area. (4 ) Although the number of reported cases is lower than the actual number of cases, a high spatial correlation exists between the cumulatively reported cases and healthcare worker cases.
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infection peak time of the epidemic in Hubei (except Wuhan) was February 2, not February 4 estimated by reported cases. (2) The estimated
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actual interval. The
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epidemic in Wuhan was approximately 63.6 days, not 45.6 days estimated by reported cases, and the infection time interval of the epidemic in Hubei (except Wuhan) was about 58.8 days, not 40.8 days estimated by reported cases. (
healthcare worker cases. (
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) The impact of under-reporting cases on the early stages of the pandemic is greater than that on its later stages, and the impact on the early onset area is greater than that on the late onset area. (4
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the actual situation. This work provides scientific support for researchers that explore the spatiotemporal distribution of COVID-19 using the data on reported
healthcare worker