Effects of environmental factors on severity and mortality of COVID-19

Abstract

Background Most respiratory viruses show pronounced seasonality, but for SARS-CoV-2 this still needs to be documented. Methods We examined the disease progression of COVID-19 in 6,911 patients admitted to hospitals in Europe and China. In addition, we evaluated progress of disease symptoms in 37,187 individuals reporting symptoms into the COVID Symptom Study application. Findings Meta-analysis of the mortality risk in eight European hospitals estimated odds ratios per one day increase in the admission date to be 0.981 (0.973-0.988, p<0.001) and per increase in ambient temperature of one degree Celsius to be 0.854 (0.773-0.944, p=0.007). Statistically significant decreases of comparable magnitude in median hospital stay, probability of transfer to Intensive Care Unit and need for mechanical ventilation were also observed in most, but not all hospitals. The analysis of individually reported symptoms of 37,187 individuals in the UK also showed the decrease in symptom duration and disease severity with time. Interpretation Severity of COVID-19 in Europe decreased significantly between March and May and the seasonality of COVID-19 is the most likely explanation. Mucosal barrier and mucociliary clearance can significantly decrease viral load and disease progression, and their inactivation by low relative humidity of indoor air might significantly contribute to severity of the disease.

DatAC: A visual analytics platform to explore climate and air quality indicators associated with the COVID-19 pandemic in Spain

“…There are previous studies that associate temperature, solar radiation, wind speed or rainfall with COVID-19 cases or deaths in different regions ( Bashir et al, 2020a ; Guasp et al, 2020 ; Kifer et al, 2020 ; Liu et al, 2020 ; Luo et al, 2020 ; Pequeno et al, 2020 ; Rosario et al, 2020 ; Tosepu et al, 2020 ; Wang et al, 2020 ). However, generally there are contradictory and/or inconclusive findings.…”

“…Regarding weather conditions, there are several studies that have been published during recent months reporting negative correlation between temperature and COVID-19 cases (see for example Luo et al, 2020 ; Pequeno et al, 2020 ; Wang et al, 2020 ), humidity and death counts ( Ma et al, 2020 ) or rainfall and new daily cases ( Menebo, 2020 ). A recent study followed almost 7000 hospitalized patients from Europe and China and reported that the increase in ambient temperature is linked to less severe symptoms ( Kifer et al, 2020 ).…”

Water-SARS-CoV-2 Interaction-Based Mechanism Inhibiting Virus Attachment to Host Cells

“…The above studies show that humidity acts not only as a non-pharmaceutical intervention for influenza but furthermore, in a sense, the surrounding water can be regarded as antiviral against the enveloped viruses [20], [23]. Viral envelope proteins from a variety of human pathogens including SARS, HIV-1, and influenza virus are extensively glycosylated [24], [25].…”

Effect of temperature and precipitation on the daily new cases and daily new death in seven cities around the globe

“…(Casanova et al, 2010) It was suggested that the coronaviruses transmit more easily during cold weathers. (Kifer et al, 2020) Even in the case of SARS-COV-2, meteorological factors seem to influence the spread of the virus. (Xu et al, 2020) It was observed that the highest outbreaks were in colder regions when Assuming that different climatic conditions affect transmission of SARS-COV-2 differently, it is important to find the association between minimum temperature, maximum temperature, average temperature, precipitation and COVID-19 incident cases and COVID-19 deaths.…”