Meteorological factors and domestic new cases of coronavirus disease (COVID-19) in nine Asian cities: A time-series analysis

Zonglin He; Yiqiao Chin; Jian Huang; Yi He; Babatunde O. Akinwunmi; Shinning Yu; Casper J.P. Zhang; Wai-kit Ming

In December 2019, several cases of pneumonia with an unknown etiology were reported in Wuhan, Hubei province, China (1) . A novel strain of coronavirus was identified from the nasopharyngeal swab specimens of the infected, which was later designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the resulting pneumonia as coronavirus disease . With the number of the infected soaring up, on 31 st January, 2020, the World Health Organization (WHO) has declared the outbreak of COVID-19 as a public health emergency of international concern (PHEIC) (2) . SARS-CoV-2, pertaining to the Coronaviridae, is an enveloped, single-stranded, positive-sense RNA virus, which is closely related to SARS-like coronaviruses, and based on the phylogenetic analysis, these coronaviruses have a common ancestor that resembles the bat coronavirus HKU9-1 (3, 4) . Evidence has shown that the SARS-CoV-2 can transmit between human through respiratory droplets, fecal-oral route, direct contacts, and aerosols (5) (6) (7) . Moreover, the long incubation period (1 to 14 days) increases the difficulty of controlling the COVID-19 outbreak. Studies have shown the mean incubation period was 5.1 days (ranged from 2.2 to 11.5 days, 95% confidence interval (CI): 4.5-5.8) (8) , and another study estimated the mean incubation period to be 6.4 days (ranged from 2 to 14 days) (9) . By March 28, 2020, more than 199 countries had confirmed cases, with more than 571,678 confirmed cases and 26,494 mortalities globally, among which 489,337 (85.6%) confirmed cases and 23,188 (87.5%) mortalities were reported outside of China (10) .