We aimed to analyze factors impacting the Covid-19 epidemic on a macro level, comparing multiple countries across the world and verifying the occurrence at a micro level through cluster analysis. The severity of the epidemic was most strongly related to exposure to ultraviolet light and extrapolated levels of vitamin D and to the health of the population, especially with regards to obesity. We found no county with an obesity level < 8% with a severe epidemic. We also found that countries where the population benefited from sun exposure or vitamin D supplementation and spent time outside fared well. Factors related to increased propagation of the virus included the use of heating ventilation and air conditioning (HVAC), population density, poorly aerated gatherings, relative humidity, timely policies of closing clustering places until aeration was improved, and daily amount of ridership on public transportation, especially subways. Population lockdowns, masks, and blood type did not provide much explanatory power. Contact tracing was not analyzed as very few countries applied it for long enough. The excess mortality observed is within the ranges of severe past influenza epidemics of 2016/2017 or 1999/2000 and lower than older severe influenza epidemics of the 1940s or 1970s. We estimated that COVID mortality death counts in European countries is over estimated when taking into account excess mortality further confirming the important role of comorbidities independently of lockdown policy. A few countries observed an under-mortality despite of some deaths counts attributed to COVID-19. Treatments or vaccines should protect the fraction of the population that is not suffering from severe comorbidities. Our study suggested that prevention measures should be directed to improving aeration systems, enhancing diets and exercise, and ensuring adequate levels of vitamin D. Prevention measures and attention should be paid to anxiety resulting from this episode which may be associated with increases in obesity, addictions, vitamin D deficiency, depression, suicide, and hunger ultimately weakening population resiliency.
Understanding SARSCOV-2 propagation, impacting factors to derive possible scenarios and simulations