The existing literature has analyzed the epidemiological characteristics of different types of COVID-19 cases, but there is still a lack of research on the epidemiological characteristics of the disease outside the Wuhan area, especially in Shenzhen, an immigrant city. This paper intended to study the epidemiological characteristics of 417 cases of COVID-19 confirmed in Shenzhen, so as to provide reasonable suggestions for the prevention and control to highly pathogenic respiratory infectious disease in the future.

Through the Health Committee of Shenzhen, Shenzhen government hotline and Sohu.com, we collected COVID-19 confirmed cases in Shenzhen, between January 1, 2020 and February 24, 2020 (Guangdong province launched a level-1 response to a major public health emergency), and data of district resident population, household register population, area, GDP, etc. Three distribution, cluster cases and mortality of all confirmed patients were analyzed. Furthermore, the first-level response to a major public health emergency initiated in Guangdong province on January 23, 2020 was taken as the time node to analyze the differences in its epidemiological characteristics before and after that.

By February 24, 2020, a total of 417 cases of COVID-19 had been diagnosed, including 197 males (47.2%) aged 2-86 years and 220 females (52.8%) aged 1-79 years, with an overall mean age of 45.3±17.6 years. Spatial distribution in Nanshan district was the most with 87 people (20.9%), and Dapeng new area was the least with 2 people (0.5%). There was a correlation between the number of patients and the number of registered population, but there was no significant correlation between the number of resident population, area, GDP, population density, per capita GDP. The onset time was from January 1, 2020 to February 14, 2020, with most cases occurring between January 16, 2020 and February 10, 2020. Eleven (2.6%) were asymptomatic and two (0.5%) developed symptoms after admission. The mean time from onset to admission was 3.0 days (range from 1 to 6 days). Among them, 77 (22.4%) fell ill before arriving in Shenzhen, and 269 (78.4%) fell ill after arriving in Shenzhen. There were 215 (51.6%) clustered cases, most of which were family clusters. There were 3 deaths (0.7%).

The age structure of confirmed COVID-19 cases in Shenzhen is consistent with the national data, but there are differences in gender distribution, which may be related to the demographic characteristics of the imported cases. Most of the cases are imported cases, suggesting that travel control and isolation should be strengthened during the epidemic period. There are obvious differences in the distribution of patients in each administrative region. The regions with large registered population have a large number of patients. The onset time of patients is mostly concentrated after the first-level response of public health emergency has started in Guangdong province. Cluster cases are more common, and predomiently mild disease suggesting that we should pay attention to publicity, improve the attention of the masses to reduce close contact; at the same time, the elderly with chronic disease should be focused on the monitoring.