COVID-19 and climatic factors: A global analysis

Abstract

Background:It is unknown if COVID-19 will exhibit seasonal pattern as other diseases e.g., seasonal influenza. Similarly, some environmental factors (e.g., temperature, humidity) have been shown to be associated with transmission of SARS-CoV and MERS-CoV, but global data on their association with COVID-19 are scarce.Objective: To examine the association between climatic factors and COVID-19.Methods: We used multilevel mixed-effects (two-level random-intercepts) negative binomial regression models to examine the association between 7- and 14-day-lagged temperature, humidity (relative and absolute), wind speed and UV index and COVID-19 cases, adjusting for Gross Domestic Products, Global Health Security Index, cloud cover (%), precipitation (mm), sea-level air-pressure (mb), and daytime length. The effects estimates are reported as adjusted rate ratio (aRR) and their corresponding 95% confidence interval (CI).Results: Data from 206 countries (until April 20, 2020) with ≥100 reported cases each showed no association between COVID-19 cases and 7-day-lagged temperature, relative humidity, UV index, and wind speed, after adjusting for potential confounders, but a positive association with 14-day-lagged temperature and a negative association with 14-day-lagged wind speed. Compared to an absolute humidity <5g/m 3 , an absolute humidity of 5-10g/m 3 was associated with a 23% (95% CI:6-42%) higher rate of COVID-19 cases, while absolute humidity >10g/m 3 did not have a significant effect. These findings were robust in the 14-day-lagged analysis.Conclusion: Our results of higher COVID-19 cases (through April 20) at absolute humidity of 5-10g/m 3 may be suggestive of a ‘sweet point’ for viral transmission, however only controlled laboratory experiments can decisively prove it.

COVID-19 incidence and mortality in Lombardy, Italy: An ecological study on the role of air pollution, meteorological factors, demographic and socioeconomic variables

“…In our study we found that a decrease in temperature and an increase in absolute humidity was associated with increasing COVID-19 incidence and all-cause mortality in a non-linear fashion, when also controlling for demographic, socio-economic and community variables. These findings are substantially in agreement with those of vast country-levels ecological studies, some of which also found a non-linear relationship between meteorological factors and COVID-19 incidence ( Guo et al, 2020 ; Islam et al, 2020 ; Y. Wu et al, 2020 ; Yuan et al, 2020 ).…”

“… Wu et al, 2020 ). Also, the role of meteorological factors on COVID-19 incidence and mortality have been investigated in several studies ( Guo et al, 2020 ; Islam et al, 2020 ; Y. Wu et al, 2020 ; Yuan et al, 2020 ).…”

Investigating the Potential for Ultraviolet Light to Modulate Morbidity and Mortality From COVID-19: A Narrative Review and Update

“…However, no significant associations were observed between 7 or 14 day-lagged measurements of the UV Index and COVID-19 incidence, following adjustment for other environmental factors as well as GDP and global health security index for data collected across 206 countries/regions (January–April 2020) ( 43 ). Similarly, in a study of people living in 224 Chinese cities, no significant associations between ambient UV levels and COVID-19 incidence rate (January–March 2020) were observed ( 44 ).…”

Social, economic, and environmental factors influencing the basic reproduction number of COVID-19 across countries

“…All of these categories have been suggested previously as possible factors for COVID-19 transmission. The most common factors previously studied were temperature (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24), pollution (13,(25)(26)(27)(28)(29)(30)(31), precipitation/humidity (18,32,33), population density (34,35), age structure (1,36,37), and population size (1,11,31). For these and additional covariates either previously studied or only mentioned in the media, we rely on statistics measured at a national level.…”