A Tempo-geographic Analysis of Global COVID-19 Epidemic Outside of China.

Background: Understanding the global epidemic trends, geographic distribution, and transmission patterns of COVID-19 contribute to providing timely information for the global response of the epidemic. This study aims to understand the global pandemic geospatial patterns and trends and identify new epicenters requiring urgent attention.

Methods: Data on COVID-19 between 31 Dec. 2019 and 14 Mar. 2020 was included. The epidemic trend was analyzed using joinpoint regressions; the growth of affected countries was by descriptive analysis; and the global distribution and transmission trend by spatial analysis.

Findings: The number of new cases in the regions outside of China slowly increased before 24 Feb. and rapidly accelerated after 24 Feb. Compared to China, other affected countries experienced a longer duration of a slow increase at the early stage and rapid growth at the latter stages. The first apparent increase in the number of affected countries occurred from 23 Jan to 1 Feb, and the second apparent increase started from 25 Feb. The fist COVID-19 cases reported by countries from 28 Feb. were mainly imported from Europe. The geographic distribution changed from single-center (13 Jan. - 20 Feb.) to multi-centers pattern (20 Feb. - 14 Mar.). More countries were affected with COVID-19 and developed local transmission.

Interpretation: The joinpoint regression and geospatial analysis indicated a multi-center pandemic of COVID-19. Strategies to prevent the new multiple centers as well as prevent ongoing transmission are needed.

Funding: NIH.