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 6,914 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 seven European hospitals estimated odds ratios per 1-day increase in the admission date to be 0.981 (0.973–0.988, p < 0.001) and per increase in ambient temperature of 1°C 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 the 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.

Social Distancing Associations with COVID-19 Infection and Mortality Are Modified by Crowding and Socioeconomic Status

“…Other measures apart from social distancing have been implemented to mitigate the spread of infection including wearing masks [36], which also impacts the generalizability of our findings as different countries have utilized different public health control measures [37]. In addition, other variables that should be considered include testing coverage, contact tracing, quarantine of contacts, isolation of non-severe cases, social support, and environmental factors (e.g., humidity, temperature) that have been shown to be associated with the severity of illness and mortality due to COVID-19 [38]. Our models were generally robust to adjustment for many potential confounders, but given our ecological study design, this cannot be ruled out.…”

Genomic Surveillance of Circulating SARS-CoV-2 in South East Italy: A One-Year Retrospective Genetic Study

“…Although it is clear that mortality rates are different from region to region and virulence is variable from person to person [ 24 , 25 , 26 , 27 ], analysis of the SARS-CoV-2 genome is crucial to understanding the pathogenesis, transmission, and spread of COVID-19. Since the publication of the first SARS-CoV-2 genome, scientists around the world have quickly realized the immediate necessity to obtain larger genetic information from as many viral genomes as possible.…”

AIDS and COVID-19 in southern Africa

“…Some governments opted for partial or national lockdowns to contain SARS-CoV-2. By the time South Africa's president Cyril Ramaphosa announced that a national lockdown would commence at midnight on 26 March, at least a fifth of the global population was sequestered, including India (24 March), China (23 January), France (17 March), Italy (10 March), New Zealand (26 March), Poland (13 March) and the UK on 23 March (Cuthbertson, 2020;Kaplan, 2020;Jones, 2020;Wade, 2020). Apart from restricting the movement of citizens internally, many countries closed their borders and cancelled international travel (Merrick, 2020).…”

“…In April 2020, Emily Wong of the Africa Health Research Institute at the University of KwaZulu-Natal in South Africa warned that "HIV infection may also affect SARS-CoV-2 infection and COVID-19 severity" (Medical Brief, 2020). Kinfu et al (2020) specifically mentioned the prevalence of HIV as one of eleven primary causes associated with a rise in COVID-19 numbers in Africa. About 7.7 million people in South Africa are HIV-positive, and 60% of those also have tuberculosis (TB) (Wild, 2020).…”