TUESDAY, March 17, 2020 (HealthDay News) -- Cities that have experienced significant outbreaks of coronavirus 2019 (COVID-19) have similar winter climates, according to a study published online March 9 on the open-data site SSRN.
Mohammad M. Sajadi, M.D., from the University of Maryland School of Medicine in Baltimore, and colleagues examined seasonal variation in COVID-19, caused by SARS-CoV-2.
The researchers note that community transmission of COVID-19 occurred in a consistent east and west pattern, with new epicenters of the virus all approximately along the 30- to 50-degree North corridor, affecting South Korea, Japan, Iran, and Northern Italy. During the same period, COVID-19 did not spread significantly to countries immediately south of China. In Southeast Asia, the number of patients and reported deaths was much less than in more temperate regions. Similar results were seen in analyses using 2-meter rather than hPa temperatures from 2020. Similarity was also seen in measures of average temperature (5 to 11 degrees Celsius) and relative humidity (47 to 79 percent) in the month of January 2020 in Wuhan and February 2020 in other affected areas. In addition, these locations have a commonality in that the outbreak timing coincided with a nadir in yearly temperatures. Furthermore, none of the affected cities had minimum temperatures below 0 degrees Celsius.
"Based on what we have documented so far, it appears that the virus has a harder time spreading between people in warmer, tropical climates," Sajadi said in a statement.