Tuesday, March 10, 2020

On COVID-19 Seasonality

by Calculated Risk on 3/10/2020 09:55:00 AM

The Flu is seasonal. There are research papers on why this happens, and it is very possible that COVID-19 will be seasonal too.

Here is an optimistic paper that suggests seasonality: Temperature and Latitude Analysis to Predict Potential Spread and Seasonality for COVID-19

A significant number of infectious diseases display seasonal patterns in their incidence, including human coronaviruses. We hypothesize that SARS-CoV-2 does as well. To date, Coronavirus Disease 2019 (COVID-19), caused by SARS-CoV-2, has established significant community spread in cities and regions only along a narrow east west distribution roughly along the 30-50 N” corridor at consistently similar weather patterns (5-11OC and 47-79% humidity). ...
COVID-19 Click on graph for larger image.
Because of geographical proximity and significant travel connections, epidemiological modeling of the epicenter predicted that regions in Southeast Asia, and specifically Bangkok would follow Wuhan, and China in the epidemic.7 However, the establishment of community transmission has occurred in a consistent east and west pattern. The new epicenters of virus were all roughly along the 30-50o N” zone; to South Korea, Japan, Iran, and Northern Italy. After the unexpected emergence of a large outbreak in Iran, we first made this map in late February. Since then new areas with significant community transmission include the Northwestern United States and France. Notably, during the same time, COVID-19 failed to spread significantly to countries immediately south of China. The number of patients and reported deaths in Southeast Asia is much less when compared to more temperate regions noted above.
This suggests temperature and humidity may be factors in the spread of COVID-19. If this is the case, then the spread of the disease might slow sharply in May.

This is a possibility, but not a certainty. If there is seasonality, we need to prepare for a resurgence of the disease in the Fall.